An alkaline dry cell includes a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an electrolytic solution contained in the positive electrode, the negative electrode, and the separator, wherein the electrolytic solution contains an alkaline aqueous solution. The negative electrode contains an additive and a negative electrode active material containing zinc; and the additive contains at least one selected from the group consisting of benzoic acid, phthalic acid, isophthalic acid, and salts of the foregoing. The amount of the negative electrode active material contained in the negative electrode is from 176 to 221 parts by mass relative to 100 parts by mass of water contained in the electrolytic solution. The amount of the additive contained in the negative electrode is from 0.1 to 1.0 part by mass relative to 100 parts by mass of the negative electrode active material.

An alkaline electrochemical cell includes a cathode; a gelled anode having an anode active material and an electrolyte; and a separator disposed between the cathode and the anode; wherein the separator includes a non-conductive, porous material having a mean pore size of about 1 micron to about 5 microns, a maximum pore size of about 19 microns, and an air permeability of about 0.5 cc/cm.sup.2/s to about 3.8 cc/cm.sup.2/s at 125 Pa.

An alkaline electrochemical cell has a central cathode having a corresponding cathode current collector electrically connected with a positive terminal of the electrochemical cell. The cathode current collector has a tubular shape, such as a cylindrical shape or rectangular shape, extending parallel with the length of the central cathode. The cathode current collector is embedded within the central cathode, such as at a medial point of a radius of the central cathode, thereby minimizing the distance between the cathode current collector and any portion of the central cathode, thereby increasing the mechanical strength of the cathode and facilitating charge transfer to the cathode current collector.

An alkaline electrochemical cell has a central cathode having a corresponding cathode current collector electrically connected with a positive terminal of the electrochemical cell. The cathode current collector has a tubular shape, such as a cylindrical shape or rectangular shape, extending parallel with the length of the central cathode. The cathode current collector is embedded within the central cathode, such as at a medial point of a radius of the central cathode, thereby minimizing the distance between the cathode current collector and any portion of the central cathode, thereby increasing the mechanical strength of the cathode and facilitating charge transfer to the cathode current collector.

A biodegradable solid aqueous electrolyte composition, an electrochemical device incorporating the electrolyte composition, and methods for the same are provided. The electrolyte composition may include a hydrogel of a copolymer and a salt dispersed in the hydrogel. The copolymer may include at least two polycaprolactone chains attached to a polymeric center block. The electrochemical device may include an anode, a cathode, and the electrolyte composition disposed between the anode and the cathode. The electrolyte composition may include a crosslinked, biodegradable polymeric material that is radiatively curable prior to being crosslinked.

To provide a separator which has a combination of a preferable air permeability enabling high prevention of internal short circuit and a high retention rate of such an air permeability in an electrolytic solution, and has more improved uniformity of the air permeability. A separator comprising a porous sheet and cellulose nanofibers, wherein the porous sheet comprises a binder component having the SP value of 11 to 16 (cal/cm.sup.3).sup.1/2, and the porous sheet has the cellulose nanofibers at the inside and on the surface thereof, and wherein the cellulose nanofibers are combined with the porous sheet by fusion of the binder component.

To provide a separator which has a combination of a preferable air permeability enabling high prevention of internal short circuit and a high retention rate of such an air permeability in an electrolytic solution, and has more improved uniformity of the air permeability. A separator comprising a porous sheet and cellulose nanofibers, wherein the porous sheet comprises a binder component having the SP value of 11 to 16 (cal/cm.sup.3).sup.1/2, and the porous sheet has the cellulose nanofibers at the inside and on the surface thereof, and wherein the cellulose nanofibers are combined with the porous sheet by fusion of the binder component.

An alkaline dry battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an alkaline electrolytic solution contained in the positive electrode, the negative electrode and the separator. The negative electrode includes a negative electrode active material including zinc, and an additive. The additive includes at least one selected from the group consisting of maleic acid, maleic anhydride and maleate salts.

A metal-ion battery is provided. The metal-ion secondary battery includes a first chamber, a second chamber, and a control element. A positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a first electrolyte are disposed within the first chamber. A second electrolyte is disposed within the second chamber, and wherein components and/or concentration of the first electrolyte are different from those of the second electrolyte. The control element determines whether to introduce the second electrolyte disposed within the second chamber into the first chamber via a first pipeline.

A metal-ion battery is provided. The metal-ion secondary battery includes a first chamber, a second chamber, and a control element. A positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a first electrolyte are disposed within the first chamber. A second electrolyte is disposed within the second chamber, and wherein components and/or concentration of the first electrolyte are different from those of the second electrolyte. The control element determines whether to introduce the second electrolyte disposed within the second chamber into the first chamber via a first pipeline.