Method of preparing anion co-doped lithium-rich manganese-based solid solution anode material

Abstract

The invention discloses a method of preparing an anion co-doped lithium-rich manganese-based solid solution anode material, which belongs to the field of lithium ion battery anode materials. Soluble metal salt and soluble phosphate are dissolved in secondary deionized water to prepare a mixture solution; a polymer is dissolved in ethanol to prepare a polymer solution; the polymer solution and themixture solution are then mixed uniformly, and a precursor is prepared by using an electrospinning device; and finally, the obtained precursor and fluoride are uniformly mixed in a molar ratio and calcined in an oxygen atmosphere to obtain the anion co-doped lithium-rich manganese-based solid solution anode material. The preparation method is simple, the reaction process is quick and simple, doping the phosphate of the anode material is added by the precursor, the doping is more uniform, step doping of fluoride is carried out during the calcining process through high temperature induction, surface side reaction and oxygen loss during the charging and discharging process of the first cycle are suppressed, the first cycle efficiency is improved, the anode material structure is effectively stabilized by polyanion, and the cycle stability of the material is improved.

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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