Anode material of lithium ion cell and preparation method thereof

Abstract

The invention discloses a preparation method of an anode material of a lithium ion cell, comprising the following steps of: (1) uniformly dispersing a Li source, a Mn source, a Ni source, a doping element and a metal element with superionic conductor attributes to prepare a precursor, wherein the metal element with the superionic conductor attributes is selected from two or two more of Ti, La andZr; (2) drying or igniting the precursor, then carrying out pretreatment to obtain pretreatment powder; (3) pressing the pretreatment powder into a sheet; (4) carrying out heat treatment for 6-24h; and (5) annealing, naturally cooling to room temperature, grinding, and sieving to obtain the anode material. In the invention, on the one hand, a crystal skeleton of the material and a Mn valence state are stabilized by using the doping element, on the other hand, a compound lithium ion superionic conductor improves a migration rate of the lithium ion in the material and improves the multiplying power property and cycling property of an electrode are improved.

Description

technical field [0001] The invention relates to a positive electrode material of a lithium ion battery and a preparation method thereof, in particular to a 5V level lithium ion battery positive electrode material LiMn 1.5 Ni 0.5 o 4 And preparation method thereof, especially refer to the LiMn of doping-lithium ion superionic conductor compound 1.5 Ni 0.5 o 4 Cathode materials and their preparation techniques. Background technique [0002] A lithium-ion battery is a rechargeable battery that primarily relies on the movement of lithium ions between positive and negative electrodes to function. During the charging and discharging process, Li + Intercalation and deintercalation back and forth between two electrodes: when charged, Li + It is deintercalated from the positive electrode, inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. Lithium-ion batteries have the adv...

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Problems solved by technology

[0004] However, in the preparation of LiMn 1.5 Ni 0.5 o 4 During the process, high temperature synthesis is likely to cause oxygen deficiency in the spinel structure, so there is an undue amount of Mn in the material. 3+ , especially when the temperature is higher than 750°C, Ni 3+ and Li x Ni 1-x The O impurity phase makes the phase change serious during the charging and discharging process of the electrode, and the electrochemical performance deteriorates, resulting in rapid capacity decay during the material cycle, and the cycle life cannot meet the actual application requirements.

However, low temperature (below 700 °C) can prepare LiMn with small stoichiometric ratio shift, stable structure and excellent cycle performance. 1.5 Ni 0.5 o 4 Positive electrode material, however, the material has poor ionic conductivity and poor rate charge and discharge performance, which cannot meet the high power density requirements of electric vehicles

[0005] In order to eliminate the high temperature synthesis of LiMn 1.5 Ni 0.5 o 4 Mn in 3+ , many researchers use doping Mg, Al, Ti, Cr, Cu, Fe, Zn, Co, Mo, etc., although cation doping helps to stabilize the valence state of Mn and eliminate the Mn in the material 3+ and Li x Ni 1-x O impurity phase, which improves the stability of the lattice and suppresses the John-Teller effect, but these cation doping usually lead to a decrease in the specific capacity and rate performance of the material

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