A copper nitride modified lithium battery material, a preparation method and an application thereof

Abstract

The invention provides a copper nitride modified lithium battery material and a preparation method and application thereof, wherein the lithium battery material comprises a lithium battery base material and a copper nitride coated on or incorporated into the lithium battery base material, wherein the copper nitride is of the formula CuAN, wherein 0.5 <= A <= 4. The copper nitride modified lithiumbattery material provided by the invention can effectively inhibit the lithium dendrite growth of the lithium battery and improve the cycling performance. The battery provided by the invention has better safety, cycle life, power density, magnification performance, energy efficiency and storage life.

Description

technical field [0001] The invention relates to the fields of new energy material technology, lithium battery material technology and electrode interface modification technology, in particular to a copper nitride modified lithium battery material and its preparation method and application. Background technique [0002] Lithium batteries have the highest energy density among all commercial batteries and are widely used in consumer electronics, electric vehicles, and large-scale energy storage. In recent years, the rapid development of various industries has put forward higher requirements for battery life, energy density, rate performance and safety. [0003] The capacity released by the graphite negative electrode in production is close to its theoretical limit. The silicon-containing negative electrode and the composite metal lithium negative electrode have extremely high theoretical capacity, and are the optional negative electrodes for future batteries. However, both sil...

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Problems solved by technology

[0004] The above schemes or approaches all have certain effects, but they also have obvious shortcomings, and have not been widely used commercially.

Specifically, the preparation of metal lithium composite electrodes requires lithium powder to be combined with carbon electrodes. The extremely high reactivity of lithium powder brings great safety hazards, and lithium alloys will be pulverized after cycling; using the method of changing the charging and discharging mode Practical application is difficult; for the electrolyte modification scheme, it is difficult to process and prepare the nanostructured electrolyte, and the high-salt concentration electrolyte has high cost and low wettability; liquid electrolyte additives are an important modification method, such as Cs + The additive has higher reactivity, but the cost is high, and the lithium nitrate additive will cause the release of NO and other gases, causing the battery to swell and even explode; the double salt LiTFSI / LiFSI (LiTFSI is lithium bistrifluoromethanesulfonylimide, LiFSI is Lithium bisfluorosulfonyl imide) or triple salt LiTFSI / LiBOB / LiPF 6 (LiBOB is lithium bisoxalate borate) system can improve battery efficiency and alleviate capacity loss; VC, FEC, and VEC can effectively form films, but the surface SEI will still be broken under long-term cycles in this process, and electrolyte additives are generally consumable. Additives, additives will always be exhausted after a long cycle, affecting the cycle performance of the battery; the main problem of using polymer solid electrolyte materials to protect high-capacity negative electrodes is low ion conductivity and poor mechanical properties, and the general electrochemical window is less than 3.8 V, cannot use lithium cobalt oxide, ternary positive electrode materials and other positive electrode materials with higher voltage, although the conductivity can be improved by using linear or grafted polymer solid electrolytes, and the mechanical properties of grafted polymers are better, but the cost Higher, the conductivity of the network polymer is also very small; the inorganic solid electrolyte has a wide electrochemical window, the chemical environment is stable, non-volatile, non-flammable, and the side reactions of the high-capacity negative electrode and the solution are eliminated, and the mechanical properties are high. The negative electrode can be flattened under high pressure. However, the conductivity of the inorganic solid electrolyte is generally low, and the rate performance is poor. Due to the large volume expansion of the high-capacity negative electrode, the physical contact with the inorganic solid electrolyte becomes poor, and the positive electrode also has a large volume expansion. The interface with the solid electrolyte will also deteriorate, and there will also be safety issues of dendrite penetration, and the expansion work will also reduce energy efficiency. In addition, the oxide solid electrolyte has poor toughness and is fragile, and the battery structure design is difficult, such as the Chinese patent The interface of LiPON solid electrolyte, sulfide solid electrolyte, positive electrode material, and high-capacity negative electrode mentioned in CN03115669 is unstable, and a buffer layer needs to be coated, and the safety of the sulfide electrolyte is doubtful, and the inorganic-organic composite electrolyte also has a large interface impedance And other issues

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