CN-122025897-A - Preparation of MSnO by recycling ternary lithium positive electrode3Method for preparing@S/C lithium sulfur anode

Abstract

The invention discloses a method for preparing a MSnO 3 @S/C lithium sulfur positive electrode by recycling a ternary lithium positive electrode. The method adopts a strategy of treating waste by waste and avoiding separation and reconstruction, firstly carries out acid leaching treatment on the positive electrode waste of the retired ternary lithium battery to obtain leaching liquid rich in Ni, co and Mn mixed transition metal ions, then directly introduces a tin source without separation and purification, synthesizes a mixed transition metal stannate (MSnO 3 , M=Ni, co and Mn) precursor through liquid phase reaction in-situ induction, and finally obtains a final product through high-temperature calcination. The material is used as a polar additive for the positive electrode of a lithium sulfur battery, and utilizes the catalytic activity of transition metal sites and the chemical adsorption effect of a tin-based framework to construct an adsorption-catalysis dual-function interface, so that polysulfide shuttle effect is effectively inhibited. The invention omits the high metal separation cost in the traditional recovery, realizes the high-value utilization of the retired battery, and remarkably improves the cycle stability and specific capacity of the lithium-sulfur battery.

Inventors

• LI ZHUOJUN
• HE JIARUI
• XI GUOBIN
• Lu Jichong
• Zhong Xiaodie
• WANG JIE

Assignees

• 东南大学

Dates

Publication Date

20260512

Application Date

20260319

Claims (9)

1. 1. A method for preparing MSnO 3 @S/C lithium sulfur positive electrode by recycling ternary lithium positive electrode is characterized by comprising the following steps: dispersing the retired ternary lithium battery anode powder in an acid solution, adding a reducing agent for leaching reaction, and filtering to remove impurities to obtain a mixed metal salt leaching solution rich in nickel, cobalt and manganese ions; Adding a tin source solution into the mixed metal salt leaching solution, uniformly mixing, adding a precipitator to adjust the pH value, and performing liquid phase reaction, centrifuging, washing and drying the product to obtain a mixed metal hydroxy stannate precursor, wherein in the liquid phase reaction, nickel, cobalt and manganese ions in the mixed metal salt leaching solution react with a tin source in situ to generate the precursor; and C, calcining the precursor at high temperature in an oxygen-containing atmosphere, naturally cooling, and grinding to obtain the mixed transition metal stannate MSnO 3 , wherein M is Ni, co and Mn.
2. 2. The method according to claim 1, wherein in the step A, the acidic solution is sulfuric acid solution with the mass concentration of 98%, the reducing agent is hydrogen peroxide solution with the mass concentration of 30%, the leaching reaction temperature is 60-90 ℃, and the reaction time is 1-4 hours.
3. 3. The method of claim 1, wherein in step B, the tin source is tin tetrachloride pentahydrate SnCl 4 ·5H 2 O.
4. 4. The method according to claim 1, wherein in the step B, the liquid phase reaction is a hydrothermal reaction, wherein the pH value is adjusted to be more than 11, the mixed solution is transferred to a high-pressure reaction kettle, and the reaction is carried out for 15 hours at 180 ℃.
5. 5. The method according to claim 1, wherein in the step B, the liquid phase reaction is a coprecipitation reaction, wherein the pH value is adjusted to 8-10, and the reaction is stirred in a water bath at 60-80 ℃ for 4-8 hours.
6. 6. The method according to claim 1, wherein in the step C, the high-temperature calcination is performed at a temperature of 500-700 ℃, a temperature rising rate of 2-5 ℃ per minute, and a heat preservation time of 2-5 hours.
7. 7. The lithium-sulfur battery tin-based positive electrode material prepared by the method according to any one of claims 1-6, wherein the main phase structure of the material is ilmenite-type or perovskite-type mixed transition metal stannate MSnO 3 , and M is Ni, co and Mn.
8. 8. The tin-based positive electrode material for the lithium-sulfur battery according to claim 7, wherein the material is used as a positive electrode additive, mixed with a sulfur/carbon composite material, a conductive agent and a binder and then coated on a current collector to prepare the modified positive electrode for the lithium-sulfur battery.
9. 9. Use of the tin-based positive electrode material for lithium sulfur batteries according to claim 7 for the preparation of a positive electrode for lithium sulfur batteries, wherein transition metal sites in the material provide catalytic activity, and wherein a tin-based skeleton provides chemisorption, together constituting an adsorption-catalysis dual function interface inhibiting polysulfide shuttling effect.

Description

Method for preparing MSnO 3 @S/C lithium sulfur positive electrode by recycling ternary lithium positive electrode Technical Field The invention belongs to the technical field of new energy material recovery and energy storage, and particularly relates to a method for preparing a MSnO 3 @S/C lithium sulfur positive electrode by recovering a ternary lithium positive electrode and an application of the ternary lithium positive electrode as a high-performance lithium sulfur battery positive electrode additive. Background With the explosive growth of the global new energy automobile industry, a ternary lithium ion battery (NCM/NCA) is used as a main power supply, and is about to be retired on a large scale. The retired ternary lithium power battery anode material is rich in key strategic metal resources such as nickel (Ni), cobalt (Co), manganese (Mn) and the like, and has extremely high metal value. However, current hydrometallurgical recovery processes generally follow the traditional route of acid leaching-impurity removal-extraction separation-precipitation. The route has obvious technical pain points that three elements of nickel, cobalt and manganese are highly similar in chemical property, and the separation difficulty is extremely high. To obtain high purity single metal salts (e.g., cobalt sulfate, nickel sulfate), plants typically require the use of expensive organic extractants (e.g., P204, P507, etc.), multiple countercurrent extraction operations in tens of stages, and tight control of pH and saponification rate. This not only results in lengthy process flows, huge capital investment (CAPEX high), extremely high reagent and energy consumption (OPEX high), but also produces large amounts of refractory high-salt organic wastewater. Therefore, the development of a separation-free short-process recycling technology directly converts mixed metal ions into high-added-value functional materials, and is an urgent need for industry cost reduction and efficiency improvement. Lithium sulfur batteries (Li-S) are considered next generation high energy storage systems following lithium ion batteries by virtue of theoretical energy densities up to 2600 Wh/kg and low cost of sulfur resources. However, its practical commercial application is still limited by the following core problems. During charge and discharge, the intermediate product lithium polysulfide (Li 2Sn, n is more than or equal to 4 and less than or equal to 8) is easy to dissolve in organic electrolyte and migrate between the anode and the cathode through a diaphragm, so that the active substance sulfur is irreversibly lost, the lithium cathode is corroded and the coulomb efficiency is rapidly reduced, the reaction kinetics are slow, the sulfur and the discharge end product (Li 2S/Li2S2) thereof are all electronic insulators, the redox reaction kinetics of the liquid phase polysulfide to solid phase lithium sulfide conversion is delayed, the rate performance of the battery is poor, and the active substance utilization rate is low. In order to solve the above problems, researchers have generally modified the positive electrode with a carbon material or a metal oxide/sulfide. The nonpolar carbon material can only provide physical barrier, has weak adsorption capacity to polar polysulfide, is difficult to inhibit shuttling for a long time, and the monometal compound has poor conductivity and limited catalytic activity of a single metal site although having chemical adsorption capacity, and is difficult to cope with complex multi-step sulfur conversion reaction. Recent studies have shown that stannate (MSnO 3) combines excellent chemical activity of tin (Sn) with d-orbital catalytic properties of transition metal (M), exhibiting excellent electrochemical performance. Particularly when a plurality of transition metals exist in the structure, the synergistic effect among different metal cations and the lattice distortion and oxygen vacancy defects introduced by the difference of ionic radii can obviously reduce the transformation energy barrier of polysulfide. However, there is no report on the preparation of such materials by using retired battery recycling solutions. The current recycling patents are mostly directed to reducing waste material to nickel cobalt lithium manganate (NCM) positive electrode precursors for re-entry into the lithium ion battery supply chain, with a single path and intense competition. Therefore, a separation-free short-flow retired battery resource utilization method is developed and applied to the preparation of high-performance positive electrode materials of lithium-sulfur batteries, and has important research value and industrialization prospect. Disclosure of Invention The invention aims to provide a preparation method for obtaining a high-efficiency stannate lithium-sulfur battery positive electrode additive based on ternary lithium retired power battery positive electrode recycling. The method aims to solve the problems o