An all-solid-state secondary battery including: a positive electrode active material layer including a positive electrode active material and a sacrificial positive electrode material having an oxidation-reduction potential which is less than a discharge voltage of the positive electrode active material; and a negative electrode active material layer including a negative electrode active material including an element alloyable with lithium or that forms a compound with lithium; and a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer, wherein the sacrificial positive electrode material includes a sacrificial active material and a conductive agent.

The present disclosure relates to a positive electrode for a lithium secondary battery, including a first positive electrode active material layer including a nickel-rich first positive electrode active material and a second positive electrode active material layer including a solid electrolyte and a second positive electrode active material. The positive electrode for a lithium secondary battery shows improved life characteristics and heat stability by virtue of the introduction of the second positive electrode active material layer.

A dispersion may include 1 to 50% by weight of lithium metal phosphate of a general formula

Li.sub.1+aM.sub.2−bN.sub.c(PO.sub.4).sub.3+d,

wherein M is Ti, Zr or Hf; N is a metal other than Li and M; 0≤a≤0.6, 0≤b≤0.6, 0≤c≤0.6, 0≤d≤0.8; and 50 to 99% by weight of trialkyl phosphate. A coating composition may include such a dispersion and such dispersions can be used in lithium ion batteries.

A dispersion may include 1 to 50% by weight of lithium metal phosphate of a general formula

Li.sub.1+aM.sub.2−bN.sub.c(PO.sub.4).sub.3+d,

wherein M is Ti, Zr or Hf; N is a metal other than Li and M; 0≤a≤0.6, 0≤b≤0.6, 0≤c≤0.6, 0≤d≤0.8; and 50 to 99% by weight of trialkyl phosphate. A coating composition may include such a dispersion and such dispersions can be used in lithium ion batteries.

To provide a method for forming a storage battery electrode including an active material layer with high density in which the proportion of conductive additive is low and the proportion of the active material is high. To provide a storage battery having a higher capacity per unit volume of an electrode with the use of a storage battery electrode formed by the formation method. A method for forming a storage battery electrode includes the steps of forming a mixture including an active material, graphene oxide, and a binder; providing a mixture over a current collector; and immersing the mixture provided over the current collector in a polar solvent containing a reducer, so that the graphene oxide is reduced.

To provide a method for forming a storage battery electrode including an active material layer with high density in which the proportion of conductive additive is low and the proportion of the active material is high. To provide a storage battery having a higher capacity per unit volume of an electrode with the use of a storage battery electrode formed by the formation method. A method for forming a storage battery electrode includes the steps of forming a mixture including an active material, graphene oxide, and a binder; providing a mixture over a current collector; and immersing the mixture provided over the current collector in a polar solvent containing a reducer, so that the graphene oxide is reduced.

A composition for forming a lithium reduction resistant layer includes a solvent, and a lithium compound, a lanthanum compound, a zirconium compound, and a compound containing a metal M, each of which shows solubility in the solvent, and in which with respect to the stoichiometric composition of a compound represented by the general formula (I), the lithium compound is contained in an amount 1.05 times or more and 2.50 times or less, the lanthanum compound and the zirconium compound are contained in an amount 0.70 times or more and 1.00 times or less, and the compound containing a metal M is contained in an equal amount.
Li.sub.7-xLa.sub.3(Zr.sub.2-x,M.sub.x)O.sub.12  (I)

A composition for forming a lithium reduction resistant layer includes a solvent, and a lithium compound, a lanthanum compound, a zirconium compound, and a compound containing a metal M, each of which shows solubility in the solvent, and in which with respect to the stoichiometric composition of a compound represented by the general formula (I), the lithium compound is contained in an amount 1.05 times or more and 2.50 times or less, the lanthanum compound and the zirconium compound are contained in an amount 0.70 times or more and 1.00 times or less, and the compound containing a metal M is contained in an equal amount.
Li.sub.7-xLa.sub.3(Zr.sub.2-x,M.sub.x)O.sub.12  (I)

The present disclosure relates to the technical field of energy storage, and in particular, relates to a positive electrode, a method for preparing the positive electrode and an electrochemical device. The positive electrode includes a current collector and a positive electrode active material layer that contains positive electrode active material and is arranged on at least one surface of the current collector. An inorganic layer having a thickness of 20 nm to 2000 nm is arranged on the surface of the at least one positive electrode active material layer away from the current collector. The inorganic layer is a porous dielectric layer containing no binder, and the inorganic layer has a porosity of 10%˜60%. The positive electrode active material layer according to the present disclosure significantly improves the cycle performance, high-temperature storage performance and safety of the electrochemical device.

The present disclosure relates to the technical field of energy storage, and in particular, relates to a positive electrode, a method for preparing the positive electrode and an electrochemical device. The positive electrode includes a current collector and a positive electrode active material layer that contains positive electrode active material and is arranged on at least one surface of the current collector. An inorganic layer having a thickness of 20 nm to 2000 nm is arranged on the surface of the at least one positive electrode active material layer away from the current collector. The inorganic layer is a porous dielectric layer containing no binder, and the inorganic layer has a porosity of 10%˜60%. The positive electrode active material layer according to the present disclosure significantly improves the cycle performance, high-temperature storage performance and safety of the electrochemical device.