Li5feo4 prelithiation agent and preparation method of lithium ion capacitor and lithium ion capacitor

Abstract

The invention discloses a preparation method of a Li5FeO4 pre-lithiation agent. The preparation method comprises the steps of: (1) dissolving ferric salt and polyvinylpyrrolidone in an organic solvent, uniformly mixing the ferric salt and polyvinylpyrrolidone and then placing the mixture in a high-pressure reactor for reaction, and cooling, washing, filtering and drying a product of the reaction to obtain nanometer Fe2O3; and (2) mixing the nanometer Fe2O3 obtained in the step (1) and lithium hydroxide uniformly, performing ball-milling on the mixture, sintering the mixture after ball-millingin an inert gas atmosphere, and carrying out cooling to obtain Li5FeO4. The invention further provides a preparation method of a lithium ion capacitor adopting L5FeO4 pre-lithiation. The prepared L5FeO4 does not have strict requirement for the environment and can be coated together with a positive electrode material, the operation is simple, the pre-lithiation degree of a negative pole piece is controllable, the effect is obvious, the pre-lithiation can be realized under the existing lithium-ion battery manufacturing condition, and the production cost can be greatly reduced.

Description

technical field [0001] The invention belongs to the field of energy storage devices, and in particular relates to a lithium ion capacitor, a preparation method of a pre-lithiation agent, and the capacitor. Background technique [0002] Lithium ion capacitors have higher energy density than electric double layer capacitors and higher power density than lithium batteries. It has great application potential in emerging energy fields such as wind power, electric vehicles, and industrial equipment for power generation. Pre-lithiation technology is the core technology of lithium-ion capacitors, and it is also a recognized technical difficulty. At present, the commonly used pre-lithiation technologies in lithium capacitors mainly include negative electrode spraying lithium powder method and diaphragm lithium plating method. Among them, the negative electrode spraying lithium powder method and the diaphragm lithium plating method are very harsh on the production conditions, and it...

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Problems solved by technology

[0003] Li 5 FeO 4 It is a lithium metal oxide with an inverse fluorite structure and has a very high specific capacity, with a theoretical capacity of 867mAh g -1 , in addition, its first charge and discharge efficiency is low, therefore, Li 5 FeO 4 It is an ideal pre-intercalated lithium additive

However, the Li prepared by the traditional synthesis method 5 FeO 4 The lower capacity is mainly due to the large size of the precursor, resulting in the final synthesis of Li 5 FeO 4 The particle size is too large, which affects the Li 5 FeO 4 electrochemical performance

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