An electrochemical device which is an alkali metal battery or an alkaline earth metal battery, wherein only a positive electrode is an electrode having a perfluoropolyether group-containing compound in a surface thereof.

The invention relates to a particulate material comprising a plurality of composite particles, wherein the composite particles comprise: (a) a porous carbon framework comprising micropores and mesopores having a total pore volume of at least 0.6 cm.sup.3/g and no more than 2 cm.sup.3/g, where the volume fraction of micropores is in the range from 0.5 to 0.9 and the volume fraction of pores having a pore diameter no more than 10 nm is at least 0.75, and the porous carbon framework has a D.sub.50 particle size of less than 20 μm; (b) silicon located within the micropores and/or mesopores of the porous carbon framework in a defined amount relative to the volume of the micropores and/or mesopores.

Described herein are improved composite anodes and lithium-ion batteries made therefrom. Further described are methods of making and using the improved anodes and batteries. In general, the anodes include a porous composite having a plurality of agglomerated nanocomposites. At least one of the plurality of agglomerated nanocomposites is formed from a dendritic particle, which is a three-dimensional, randomly-ordered assembly of nanoparticles of an electrically conducting material and a plurality of discrete non-porous nanoparticles of a non-carbon Group 4A element or mixture thereof disposed on a surface of the dendritic particle. At least one nanocomposite of the plurality of agglomerated nanocomposites has at least a portion of its dendritic particle in electrical communication with at least a portion of a dendritic particle of an adjacent nanocomposite in the plurality of agglomerated nanocomposites.

A nanofluid contact potential difference cell includes a cathode with a lower work function and an anode with a higher work function separated by a nanometer-scale spaced inter-electrode gap containing a nanofluid with intermediate work function nanoparticle clusters. The cathode comprises a refractory layer and a thin film of electrosprayed dipole nanoparticle clusters partially covering a surface of the refractory layer. A thermal power source, placed in thermal contact with the cathode, to drive an electrical current through an electrical circuit connecting the cathode and anode with an external electrical load in between. A switch is configured to intermittently connect the anode and the cathode to maintain non-equilibrium between a first current from the cathode to the anode and a second current from the anode to the cathode.

A method for modifying an electrode comprising an alkali metal is disclosed, the method comprising casting a salt solution comprising at least one salt comprising an alkaline ion and a solvent on the electrode; casting a fluoropolymer solution comprising at least one fluoropolymer and a solvent on the electrode; and drying the electrode.

Also disclosed is an electrode comprising an alkali metal at least partly covered by a solid electrolyte interphase, said solid electrolyte interphase having atomic ratios of carbon, fluorine and sulfur atoms of 1 C:0.15 to 0.80 F:0.02 to 0.30 S.

A cobalt-free positive electrode material and a preparation method therefor, a lithium ion battery positive electrode, and a lithium ion battery, relating to the technical field of lithium ion batteries. The positive electrode material comprises a core and a shell covering the core, the core being a cobalt-free positive electrode material, the chemical formula of the core being LiNi.sub.xMn.sub.yO.sub.2, wherein 0.55≤x≤0.95 and 0.05≤y≤0.45, and the shell is a coating agent and carbon. The present method can improve the dispersibility of the cobalt-free positive electrode material during the coating process, and can also improve the conductivity of the cobalt-free positive electrode material.

The present invention relates to a lithium metal composite oxide powder having a layered structure, and comprising at least Li, Ni, and an element X, wherein: said element X is at least one element selected from the group consisting of Co, Mn, Fe, Cu, Ti. Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P; and the lithium metal composite oxide powder satisfies requirements (1), (2), and (3): (1) an angle of difference (θ1- θ2) calculated from an angle of repose (θ1) and an angle of fall (θ2) is 15° or less, wherein the angle of repose (θ1) is an angle of slope of the lithium metal composite oxide powder piled on a measurement table, and the angle of fall (θ2) is an angle of slope measured after application of a predetermined impact force to the measurement table; (2) an average primary particle diameter is 1 .Math.m or more; and (3) an amount of water contained in the lithium metal composite oxide powder is 1000 ppm or less.

A nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure comprises a positive electrode, a negative electrode and a nonaqueous electrolyte solution; the negative electrode comprises a negative electrode collector and a negative electrode active material layer that is provided on the negative electrode collector; the negative electrode active material layer contains, as negative electrode active materials, graphite particles A and graphite particles B; the graphite particles A have an internal void fraction of 5% or less; the graphite particles B have an internal void fraction of from 8% to 20%; if the negative electrode active material layer is halved in the thickness direction, a region on the half closer to the outer surface contains more graphite particles A than a region on the half closer to the negative electrode collector.

A negative electrode comprises a negative electrode collector, a first negative electrode mixture layer, and a second negative electrode mixture layer the ratio of the void fraction (S2) among the graphite particles in the second negative electrode mixture layer to the void fraction (S1) among the graphite particles in the first negative electrode mixture layer, namely S2/S1 is from 1.1 to 2.0: and the ratio of the packing density (D2) of the second negative electrode mixture layer to the packing density (D1) of the first negative electrode mixture layer, namely D2/D1 is from 0.9 to 1.1. A separator has a first surface that is in contact with a positive electrode and a second surface that is in contact with the negative electrode; and the contact angle of the first surface with ethylene carbonate is smaller than the contact angle of the second surface with ethylene carbonate.

A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte, wherein the negative electrode includes a negative electrode current collector and a negative electrode active material layer supported by the negative electrode current collector, when dividing the negative electrode active material layer into two layers of a first region and a second region having the same thickness, the second region is closer to the negative electrode current collector than the first region, the first region and the second region each contains graphite particles, a ratio P1/P2 of interparticle porosity P1 of the first region to interparticle porosity P2 of the second region is greater than 1, and the nonaqueous electrolyte includes at least one additive selected from the group consisting of a sulfite compound and a sulfate compound.