A kind of preparation method of lithium-rich manganese-based solid solution cathode material co-doped with anion

Abstract

A method for preparing an anion co-doped lithium-rich manganese-based solid solution cathode material. The invention belongs to the field of cathode materials for lithium ion batteries. The soluble metal salt and soluble phosphate of the present invention are dissolved in secondary deionized water to prepare a mixture solution; the polymer is dissolved in absolute ethanol to prepare a polymer solution. Then the polymer solution and the mixture solution are mixed evenly, and the precursor is prepared by using an electrospinning device. Finally, the obtained precursor and the fluoride are uniformly mixed according to the molar ratio, and roasted in an oxygen environment to obtain an anion co-doped lithium-rich manganese-based solid solution positive electrode material. The preparation method of the invention is simple, the reaction process is fast and simple, the phosphate radical of the positive electrode material is added through the precursor, and the doping is more uniform. "Oxygen loss" during the process improves the efficiency of the first cycle, and the polyanion effectively stabilizes the structure of the positive electrode material and improves the cycle stability of the material.

Description

technical field [0001] The invention belongs to the field of positive electrode materials of lithium ion batteries, and discloses a preparation method of an anion co-doped lithium-rich manganese-based solid solution positive electrode material. Background technique [0002] With the increasing application of lithium-ion batteries in the fields of electric vehicles and energy storage, there is an urgent need to reduce the cost of lithium-ion batteries while increasing their energy density. Lithium-rich manganese-based cathode material xLi 2 MnO 3 ·(1-x)LiMO 2 (M=Mn,Ni,Co) has attracted widespread attention for its reversible specific capacity up to 250mA h / g, but its application is severely restricted by its low first-week Coulombic efficiency, poor rate performance, and poor cycle performance. [0003] In order to improve the performance of lithium-rich manganese-based cathode materials, researchers have carried out modification studies on them. Modification methods main...

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Problems solved by technology

However, the current doping modification often only involves one kind of ion, which cannot improve the first-week Coulombic efficiency and cycle performance at the same time.

Xia's group (Chemistry of Materials, 2011, 23(7): 1954-1963) successfully prepared Li 1.2 Ni 0.13 co 0.13 mn 0.54 (BO 4)0.75x (BO 3 ) 0.25x o 2–3.75x , (BO 3 ) 3- and (BO 4 ) 5- The introduction of O 2 - The 2p energy band drops and decreases with the Ni 3+ / Ni 4+ The eg energy band and Co 3+ / Co 4+ The overlapping of t2g energy bands improves the thermal stability and cycle performance of lithium-rich materials, but the Coulombic efficiency has not been effectively improved for the first time.

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