Abstract
A process for preparing a stable Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material is provided. The general formula of the B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel is LixMn.sub.2-yM.sub.yO.sub.4-z(Cl.sub.z) where M is Fe, Co or Ni. In addition, a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material is provided. Furthermore, a lithium or lithium ion rechargeable electrochemical cell is provided, incorporating the Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material in a positive electrode.
Claims
1. A method of preparing a homogeneously dispersed Group VIII Period 4 element and chlorine-modified lithium manganese based AB.sub.2O.sub.4 spinel cathode material, the method comprising: dissolving a chloride of a Group VIII Period 4 element, a nitrate of a Group VIII Period 4 element, manganese nitrate, and lithium nitrate in distilled water or deionized water to produce an aqueous solution; mixing the aqueous solution with a chelating agent to produce a mixture; heating the mixture at a temperature ranging from 75 C. to 120 C. to produce a gel; heating the gel at a temperature ranging from 200 C. to 300 C. to produce an ash; grinding the ash; and calcining the ground ash for a time period no greater than 5 hours at a temperature of at least 350 C. to produce the homogeneously dispersed Group VIII Period 4 element and chlorine-modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, wherein the Group VIII Period 4 element is selected from a group consisting of iron and cobalt, and wherein the homogeneously dispersed Group VIII Period 4 element and chlorine-modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material is fully reversible at charge potentials equal to or greater than 5.2 volts and discharge potentials equal to or less than 2.0 volts.
2. The method according to claim 1, wherein the chelating agent is a compound selected from a group consisting of glycine, cellulose, citric acid, a cellulose-citric acid mixture, and urea.
3. The method according to claim 1, further comprising mixing the homogeneously dispersed Group VIII Period 4 element and chlorine-modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material with a conductive carbon and a binder.
4. The method according to claim 3, wherein the conductive carbon is selected from a group consisting of conductive carbon black, graphite, carbon nanofibers, and carbon nanoparticles and the binder is selected from a group consisting of polytetrafluoroethylene, polyvinylidene fluoride, and latex.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are included to provide further understanding of the present disclosure, and are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the present disclosure, and together with the description serve to explain the principles of the present disclosure. The present disclosure will now be described further with reference to the accompanying drawings as follows:
(2) FIG. 1 is a flowchart illustrating process steps in an exemplary embodiment of the present disclosure.
(3) FIG. 2 is a timeline chart contrasting the required fabrication times for an exemplary embodiment of the present disclosure versus conventional preparation methods.
(4) FIG. 3 is an expanded spinel formation timeline chart showing an exemplary embodiment of the present disclosure.
(5) FIG. 4 is a graph showing x-ray diffraction data for an exemplary formulation mixture according to exemplary embodiments of the present disclosure.
(6) FIG. 5 is a graph showing x-ray diffraction data for an exemplary formulation mixture according to exemplary embodiments of the present disclosure compared to known reference standards.
(7) FIG. 6 is a graph showing x-ray fluorescence data for an exemplary formulation mixture according to exemplary embodiments of the present disclosure.
(8) FIG. 7 is a graph showing x-ray fluorescence data for an exemplary formulation mixture according to exemplary embodiments of the present disclosure compared to known references.
(9) FIG. 8 is a graph illustrating representative forming cycles (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(10) FIG. 9 is a differential capacity graph illustrating the forming cycle traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(11) FIG. 10 is a plot containing the initial ten charge/discharge cycle potential trace, the charge capacity and delivered discharge capacity per cycle of an exemplary lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-y M.sub.yO.sub.4-zCl.sub.z is Fe.
(12) FIG. 11 is a plot containing the 11.sup.th to 29.sup.th charge/discharge cycle potential trace, the charge capacity and delivered discharge capacity per cycle of an exemplary lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-y M.sub.yO.sub.4-zCl.sub.z is Fe.
(13) FIG. 12 is a differential capacity graph illustrating the 11.sup.th to 29.sup.th charge/discharge cycle traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(14) FIG. 13 is a representative hysteresis cycling cycle 11.sup.th to 29.sup.th (charge/discharge) curve illustrating cycle life traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(15) FIG. 14 is a representative hysteresis cycling (charge/discharge) curve illustrating cycle initiation and completion for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(16) FIG. 15 is a plot containing the initial ten and 12.sup.th charge/discharge cycle potential trace, the charge capacity and delivered discharge capacity per cycle of an exemplary lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(17) FIG. 16 is a plot containing the initial ten charge/discharge cycle potential trace, the charge capacity and delivered discharge capacity per cycle of an exemplary lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. For this graph, the M in Li.sub.xMn.sub.2-y M.sub.yO.sub.4-zCl.sub.z is Fe.
(18) FIG. 17 is a graph illustrating representative forming cycles (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 4.5 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(19) FIG. 18 is a differential capacity graph illustrating the forming cycle traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 4.5 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(20) FIG. 19 is a differential capacity graph illustrating the high potential portion of the forming cycle traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 4.5 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(21) FIG. 20 is a differential capacity graph illustrating the low potential portion of the forming cycle traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 4.5 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(22) FIG. 21 is a graph illustrating representative forming cycles (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 4.5 and 3.5 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Co.
(23) FIG. 22 is a differential capacity graph illustrating the forming cycle traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 4.5 and 3.5 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Co.
(24) FIG. 23 is a graph illustrating representative forming cycles (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Co.
(25) FIG. 24 is a differential capacity graph illustrating the forming cycle traces for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Co.
(26) FIG. 25 is a plot containing the initial seven cycles (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 3.5 volts then 5.0 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Ni.
(27) FIG. 26 is a differential capacity graph illustrating cycle traces 6 and 7 for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Ni.
(28) FIG. 27 is a plot containing the initial seven cycles (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 2.25 volts then 5.0 and 3.5 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Ni.
(29) FIG. 28 is a differential capacity graph illustrating the forming cycles for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 2.25 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Ni.
(30) FIG. 29 is a plot containing cycles 3 and 4 (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 2.0 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Ni.
(31) FIG. 30 is a differential capacity graph illustrating cycles 3 and 4 for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.0 and 2.0 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Ni.
(32) FIG. 31 is a plot containing cycles 7 to 9 (charge/discharge) curves for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.2 and 3.5 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(33) FIG. 32 is a differential capacity graph illustrating cycles 7 to 9 for a lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 5.2 and 3.5 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
(34) FIG. 33 is a graph illustrating representative coulombic efficiency and cycle life of an exemplary lithium cell containing a Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure cycled between 4.5 and 3.5 volts. For this graph, the M in Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z is Fe.
DETAILED DESCRIPTION
(35) FIG. 1 is a flowchart illustrating process steps in an exemplary embodiment of the present disclosure. More specifically, FIG. 1 shows exemplary steps according to the present disclosure for the preparation of Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z, Where M is Fe, Co or Ni, Spinel material via a method comprising of an initial nitrate flame process followed by a calcining reaction. In step S1, a chlorine-containing salt is added to lithium nitrate, manganese nitrate and a Group VIII Period 4 element (iron, cobalt, or nickel) nitrate. Suitable chlorine-containing salts include, but are not limited to, lithium chloride, manganese chloride, iron chloride, cobalt chloride, and nickel chloride.
(36) In Step S2, the mixture is then dissolved in distilled or de-ionized water. In Step S3, glycine is then dissolved into the aqueous solution as a chelating agent. Suitable chelating agents include, but are not limited to, glycine, cellulose, citric acid, a cellulose-citric acid mixture, and urea. In Step S4, the solution is heated on a hot plate until the water fully evaporates and a gel is formed. In Step S5, the gel is heated further until auto ignition occurs and forms an ash. The ash is collected and ground in Step S6.
(37) In Step S7, the ash is calcined in a furnace at 600 C. for 2 hours. Alternatively, suitable calcination temperatures and times range from 350 C. to 800 C. (for 1 to 4 hours), from 400 C. to 600 C. (for 1.5 to 3 hours), or from 500 C. to 600 C. (for 2 to 2.5 hours). In Step S8, the mixture is cooled at a temperature ranging from 20 C. to 300 C. (for 1 to 24 hours), from 20 C. to 150 C. (for 1 to 4 hours), or from 20 C. to 50 C. (for 1 to 2.5 hours). The stoichiometric ratio in the final Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z where M is Fe, Co or Ni, material ranges from x=0.05 to 1.9, y=0.005 to 0.6, and z=0.005 to 0.25. The stoichiometric ratio in the final Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z material preferred embodiment ranges from x=0.8 to 1.3, y=0.005 to 0.3, and z=0.005 to 0.05
(38) The exemplary process described above results in the formulation of a family of Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material. The general formula for the lithium electrochemical cell cathode prepared is Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z, where M is iron, cobalt or nickel, x1 and proves to be reversible between 5.2 and 2.0 volts. This reversible region for x in a lithium electrochemical cell comprised of the present disclosure ranges from 0.05 to 1.9 and y ranges from 0.005 to 0.6 and z ranges from 0.005 to 0.25.
(39) FIGS. 2 and 3 illustrate steps and timelines for conventional fabrication methods versus the preparation methods provided in the present disclosure. These conventional solid state and hydrothermal fabrication methods are described in U.S. Pat. Nos. 5,753,202 and 5,135,732, respectively (which are incorporated by reference in their entirety). FIG. 3 shows an expanded view of the steps of an exemplary method according to the present disclosure. As shown in FIGS. 2 and 3, the entire fabrication process (including cooling time) takes over 2 or 4 days using conventional solid state and hydrothermal methods, respectively. In contrast, the entire fabrication process (including cooling time) takes approximately 4.5 hours using the present fabrication method.
(40) FIGS. 4 and 5 shows the X-ray diffraction pattern of an exemplary formulation mixture according to exemplary embodiments of the present disclosure compared to known reference standards. The figure shows the final Li.sub.xMn.sub.2-yFe.sub.yO.sub.4-zCl.sub.z material according to the present disclosure. Included in FIG. 5 is the standard data for intensity and location from the International Center for Diffraction Data for Mn.sub.2O.sub.3 and LiMn.sub.2O.sub.4 spinel. FIGS. 6 and 7 shows the X-ray Fluorescence Pattern for an exemplary formulation mixture of the present disclosure. Included in FIG. 7 is the data of the final Li.sub.xMn.sub.2-yFe.sub.yO.sub.4-zCl.sub.z material as well as intensity and energy level for the system components. These components include the palladium X-ray source and silicon and phosphorus from the sample holder.
(41) In order to evaluate the electrochemical properties of the present Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material in an electrochemical system, laboratory coin cells were fabricated using conventional methods described in detail below. Experimental cells may also be fabricated using other methods known in the art, incorporating the Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z, where M is Fe, Co or Ni, lithium manganese-based AB.sub.2O.sub.4 spinel material described in the present disclosure. The experimental cells were composed of a lithium anode separated from a Teflon bonded cathode with a nonwoven glass separator. Other suitable anode materials include, but are not limited to, lithium metal, lithium aluminum alloy, lithium silicon alloy, graphite and graphite derivatives, tin oxide, and lithium phosphate. The cathode was fabricated by combining Li.sub.xMn.sub.2-yM.sub.yO.sub.4-z Cl.sub.z, carbon, and Teflon in a 75:15:10 weight percent basis, respectively. Suitable conductive carbon materials include, but are not limited to, conductive carbon black (commercially available from various sources, including Cabot Corporation, under the trade name VULCAN XC72 or VULCAN XC72R), graphite, carbon nanofibers, and carbon nanoparticles (commercially available under the trade name PURE BLACK, manufactured by Superior Graphite Co.). Suitable binders include, but are not limited to, polytetrafluoroethylene (commercially available under the trade name TEFLON, manufactured by DuPont), polyvinylidene fluoride (PVDF), and latex. The cathode may contain by weight 40%-95% of Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z, 1%-40% of conductive carbon, and 1%-20% binder.
(42) The cathode mix was rolled to 0.06 cm and dried in a vacuum oven. The cathode mass was approximately 0.1 g. The cathode and 0.075 cm thick lithium foil was cut using a 1.58 cm diameter (1.96 cm.sup.2) hole punch. A 0.01 cm nonwoven glass separator was used for the separator and as a wick. The electrolyte used was 1 M LiPF.sub.6 in proportional mixtures of dimethyl carbonate and ethylene carbonate. Other suitable electrolytes include, but are not limited to, lithium hexafluoroarsenate monohydrate (LiAsF.sub.6), lithium perchlorate (LiClO.sub.4), lithium tetrafluoroborate (LiBF.sub.4), and lithium triflate (LiCF.sub.3SO.sub.3). The cells were cycled with an ARBIN Model MSTAT4 Battery Test System. The charge profile consisted of a constant current charge at 1.0 or 2.0 mA to 4.5, 4.75, 5.0 or 5.2 volts. The cells were discharged at 1.0 or 2.0 mA to 2.0, 2.25 or 3.5 volts. A rest period of 15 minutes between cycles allowed for the cells to equilibrate. Prior to cycling, cell impedance was recorded with a Solartron, SI1260 Frequency Response Analyzer with a Solartron, SI1287 Electrochemical Interface using Scribner Associates, Inc., ZPlot and ZView software. The data is used as a quality control tool and for comparative use between variant chemistries.
(43) The data shows stable Group VIII Period 4 element (iron, cobalt, or nickel) B site and chlorine O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material was formulated, fabricated, and characterized as a positive electrode suitable for lithium and lithium ion rechargeable electrochemical cells and batteries. The general formula for the present spinel material is Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z, where M is Fe, Co or Ni, and x ranges from 0.05 to 1.9 and y ranges from 0.005 to 0.60 and z ranges from 0.005 to 0.25 and the reversible region for x for the Li/Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z electrochemical couple ranges from 0.05 to 1.9. The specific capacity for the Group VIII Period 4 element and chlorine-modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material ranged from 100 to 125 mAh/g when coupled with lithium and cycled between 5.2 and 3.5 volts. This is comparable to conventional lithium manganese-based AB.sub.2O.sub.4 spinel materials fabricated over a 48 to 72-hour time span. Processing time according to the present disclosure has been dramatically reduced to less than 8 hours. The specific capacity for the Group VIII Period 4 element and chlorine-modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material was 195 to 205 mAh/g when coupled with lithium and cycled between 5.2 and 2.0 volts. Li/Li.sub.xMn.sub.2-yM.sub.yO.sub.4-zCl.sub.z cells cycled between 4.5 and 3.5 maintained greater than 95% of their original capacity thru 200 cycles.
(44) FIGS. 8-14 show galvanostatic (charge/discharge) and differential capacity plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure. In the exemplary plots shown in FIGS. 8-14 iron is the Group VIII Period 4 B site element in the modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material. The chlorine to manganese ratios in the final product is 0.0043 while the iron to manganese ratio is 0.0716.
(45) FIGS. 8 and 9 show exemplary forming cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure. In FIG. 10 the forming cycle charge/discharge data is presented potential verses time and, in FIG. 11 the forming cycle charge/discharge data is presented as differential capacity.
(46) FIGS. 10 and 11, shows the potential verses time data along with the charge capacity and delivered discharge capacity per cycle. FIG. 10 displays cycles 1 through 10 and FIG. 11 shows cycles 11 through 29.
(47) FIG. 12 is a differential capacity graphs of cycles 11 through 29 illustrating exemplary cycle life traces for lithium cells containing a B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. Differential capacity traces provides information regarding the underlying thermodynamics and kinetics of an electrochemical cell. The differential capacity data uses galvanostatic control of the electrochemical system being tested, and plots the capacity increase (charge) or decrease (discharge) as a function of potential. The figures show the stable thermodynamic behavior of the B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure, where Li.sub.xMn.sub.1.87Fe.sub.0.13O.sub.3.991Cl.sub.0.009 is the active cathode material and lithium is the active anode material.
(48) FIGS. 13 and 14 are the representative hysteresis cycling (charge/discharge) curve illustrating cycle life traces for a lithium cell containing a B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. FIG. 13 is a graph of cycles 11 through 29 and FIG. 14 is the same graph with the initiation and completion of the charge and discharge highlighted.
(49) FIGS. 15-20 show galvanostatic (charge/discharge) and differential capacity plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure. In the exemplary plots shown in FIGS. 15-20 iron is the Group VIII Period 4 B site element in the modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material. The chlorine to manganese ratios in the final product is 0.0098 while the iron to manganese ratio is 0.0923.
(50) FIGS. 15 and 16 are plots containing the initial ten and 12.sup.th charge/discharge cycle potential trace, along with the charge capacity and delivered discharge capacity per cycle of an exemplary lithium cell containing a B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material according to an exemplary embodiment of the present disclosure. This plot shows the added capacity delivered by the system as a result of cycling to a 2.0 volt cut off. In FIG. 10 the charge/discharge cycle data is presented as potential verses time and, in FIG. 11 the charge/discharge cycle data is presented as differential capacity.
(51) FIGS. 17 and 20 show exemplary cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.83Fe.sub.0.17O.sub.3.981Cl.sub.0.018 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 4.5 volts and discharged to a potential of 2.25 volts. In FIG. 17 the forming cycle charge/discharge data is presented potential verses time and, in FIG. 18 the forming cycle charge/discharge data is presented as differential capacity. FIGS. 19 and 20 show the high potential and low potential portion of the data shown in FIG. 18 respectively.
(52) FIGS. 21-24 show galvanostatic (charge/discharge) and differential capacity plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure. In the exemplary plots shown in FIGS. 21-24 cobalt is the Group VIII Period 4 B site element in the modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material. The chlorine to manganese ratios in the final product is 0.0021 while the cobalt to manganese ratio is 0.0873.
(53) FIGS. 21 and 22 show exemplary cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.84Co.sub.0.16O.sub.3.995Cl.sub.0.005 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 4.5 volts and discharged to a potential of 3.5 volts. In FIG. 21 the forming cycle charge/discharge data is presented potential verses time and, in FIG. 22 the forming cycle charge/discharge data is presented as differential capacity.
(54) FIGS. 23 and 24 show exemplary cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.84Co.sub.0.16O.sub.3.995Cl.sub.0.005 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 5.0 volts and discharged to a potential of 2.25 volts. In FIG. 23 the forming cycle charge/discharge data is presented potential verses time and, in FIG. 24 the forming cycle charge/discharge data is presented as differential capacity.
(55) FIGS. 25-28 show galvanostatic (charge/discharge) and differential capacity plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure. In the exemplary plots shown in FIGS. 25-28 nickel is the Group VIII Period 4 B site element in the modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material. The chlorine to manganese ratios in the final product is 0.0030 while the nickel to manganese ratio is 0.0683.
(56) FIGS. 25 and 26 show exemplary cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.87Ni.sub.0.13O.sub.3.994Cl.sub.0.006 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 5.0 volts and discharged to a potential of 3.5 volts for the first four cycles then charged to a potential of 5.0 volts and discharged to a potential of 2.25 volts. In FIG. 25 the cycle charge/discharge data is presented potential verses time and, in FIG. 26 the cycle charge/discharge data is presented as differential capacity.
(57) FIGS. 27 and 28 show exemplary cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.87Ni.sub.0.13O.sub.3.994Cl.sub.0.006 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 5.0 volts and discharged to a potential of 2.25 volts then charged to a potential of 5.0 volts and discharged to a potential of 3.5 volts. In FIG. 27 the cycle charge/discharge data is presented potential verses time and, in FIG. 28 the cycle charge/discharge data is presented as differential capacity.
(58) FIGS. 29 and 30 show galvanostatic (charge/discharge) and differential capacity plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure. In the exemplary plots shown in FIGS. 29 and 30 nickel is the Group VIII Period 4 B site element in the modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material. The chlorine to manganese ratios in the final product is 0.0132 while the nickel to manganese ratio is 0.4043.
(59) FIGS. 29 and 30 show exemplary cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.42Ni.sub.0.58O.sub.3.981Cl.sub.0.019 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 5.0 volts and discharged to a potential of 2.0 volts. In FIG. 29 the cycle charge/discharge data is presented potential verses time and, in FIG. 30 the cycle charge/discharge data is presented as differential capacity.
(60) FIGS. 31-33 show galvanostatic (charge/discharge), differential capacity plots and cycle life plot for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure. In the exemplary plots shown in FIGS. 31-33 iron is the Group VIII Period 4 B site element in the modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material. The chlorine to manganese ratios in the final product is 0.0117 while the iron to manganese ratio is 0.1195.
(61) FIGS. 31 and 32 show exemplary cycle plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.79Fe.sub.0.21O.sub.3.979Cl.sub.0.021 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 5.2 volts and discharged to a potential of 3.5 volts. In FIG. 31 the cycle charge/discharge data is presented potential verses time and, in FIG. 32 the cycle charge/discharge data is presented as differential capacity.
(62) FIG. 33 shows exemplary coulombic efficiency and cycle life plots for lithium electrochemical cells fabricated with B and O site modified lithium manganese-based AB.sub.2O.sub.4 spinel cathode material, synthesized using the method described in the present disclosure where Li.sub.xMn.sub.1.79Fe.sub.0.21O.sub.3.979Cl.sub.0.021 is the active cathode material and lithium is the active anode material. For this example the cell was charged to a potential of 4.5 and discharged to a potential of 3.5.
(63) The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments which fall within the true spirit and scope of the present disclosure. Thus, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
