CN-116417101-B - Method, equipment and storage medium for predicting oxygen release difficulty of lithium-rich manganese-based positive electrode material

CN116417101BCN 116417101 BCN116417101 BCN 116417101BCN-116417101-B

Abstract

The application provides a method, equipment and a storage medium for predicting oxygen release difficulty of a lithium-rich manganese-based positive electrode material, and relates to the technical field of new energy. According to the method, a charging process of a material is calculated and simulated through a first sexual principle, a structure of the lithium-rich manganese-based positive electrode material when lithium vacancies occur is found, oxygen is built by transition metal migration in layers or among layers on the structure, and then the difficulty degree of oxygen generation of the material is judged through transition metal migration energy barriers. The method can calculate the oxygen release difficulty of the lithium-rich manganese-based positive electrode material more accurately, predict the safety and the cycle performance of the lithium-rich manganese-based positive electrode material under high voltage more accurately, assist in finding out a structure which is not easy to generate oxygen in theory, and guide the experiment to synthesize the material with the structure, and assist in developing new materials with high safety.

Inventors

QIU KAI
TAN TIENING
ZHU GAOLONG
HUA JIANFENG
LI LIGUO
DAI FENG

Assignees

四川新能源汽车创新中心有限公司

Dates

Publication Date: 20260512
Application Date: 20230413

Claims (7)

1. The method for predicting the oxygen release difficulty of the lithium-rich manganese-based positive electrode material is characterized by comprising the following steps of: Carrying out lithium removal simulation charging process on the initial unit cell structure of the lithium-rich manganese-based anode material and generating lithium vacancies to obtain a first configuration; migrating transition metal ions to the lithium vacancies and generating oxygen to obtain a second configuration; Calculating a migration energy barrier of the transition metal ion according to the first configuration and the second configuration; Predicting the oxygen release difficulty of the lithium-rich manganese-based positive electrode material according to the migration energy barrier of the transition metal ions; the method for carrying out lithium removal simulation charging on the initial unit cell structure of the lithium-rich manganese-based positive electrode material and generating lithium vacancies to obtain a first configuration comprises the following steps: In each lithium removal, each lithium ion of the initial unit cell structure is subjected to lithium removal, configuration energy after each lithium ion is respectively subjected to lithium removal is compared, the configuration with the lowest free energy is used as the most stable lithium removal structure generated by the lithium removal, and the most stable lithium removal structure is used as the basis of the next lithium removal until the charging cut-off voltage is reached; The lithium vacancy is a transition metal layer lithium vacancy or a lithium layer lithium vacancy, and the transition metal ion is migrated to the lithium vacancy and generates oxygen to obtain a second configuration, and the method comprises the following steps: migrating the transition metal ions to the lithium vacancies such that cavities are created in the transition metal layer and isolated oxygen atoms are present in the cavities; Moving the isolated oxygen atoms to bond with surrounding oxygen atoms to generate oxygen, thereby obtaining the second configuration; said moving said isolated oxygen atoms into bonding with surrounding oxygen atoms to produce oxygen, resulting in said second configuration, comprising: and moving the isolated oxygen atoms to bond with all surrounding oxygen atoms respectively, and comparing configuration energy after bonding of each isolated oxygen atom, and taking the configuration with the lowest free energy as the second configuration.
2. The method for predicting oxygen release difficulty of a lithium-rich manganese-based positive electrode material according to claim 1, wherein the initial unit cell structure is established according to a chemical formula of the lithium-rich manganese-based positive electrode material, a space group of the lithium-rich manganese-based positive electrode material is C2/m, the chemical formula of the lithium-rich manganese-based positive electrode material is xLi 2 MnO 3 •(1-x)LiTMO 2 or Li 1+x TM y Mn 1-x-y O 2 , TM is transition metal, 0< x <1,0< y <1, and the initial unit cell structure is a configuration with the lowest free energy obtained after structural optimization under the chemical formula.
3. The method for predicting the oxygen release difficulty of a lithium-rich manganese-based positive electrode material according to claim 1, wherein the transition metal ions have a migration number of 2-3, and the isolated oxygen atoms generated after the transition metal ions migrate have a number of 1-2.
4. The method of predicting the oxygen evolution difficulty of a lithium-rich manganese based cathode material according to any one of claims 1-3, wherein the calculating the transition energy barrier of the transition metal ion from the first configuration and the second configuration comprises: And calculating the migration energy barrier of the transition metal ions by using the first configuration as an initial configuration and the second configuration as a final configuration through a climbing image inching elasticity method.
5. The method for predicting the oxygen evolution difficulty of a lithium-rich manganese-based cathode material according to claim 1, wherein predicting the oxygen evolution difficulty of the lithium-rich manganese-based cathode material according to the migration energy barrier of the transition metal ions comprises: if the migration energy barrier of the transition metal ions is less than 1eV, the lithium-rich manganese-based positive electrode material is easy to release oxygen; if the migration energy barrier of the transition metal ions is greater than or equal to 1eV, the lithium-rich manganese-based positive electrode material is difficult to release oxygen.
6. An apparatus comprising a memory and a processor, the memory storing a computer program that, when run on the processor, performs the method of predicting oxygen evolution difficulty of a lithium-rich manganese-based cathode material of any one of claims 1 to 5.
7. A storage medium storing a computer program which, when run on a processor, performs the method of predicting oxygen evolution difficulty of a lithium-rich manganese-based cathode material according to any one of claims 1 to 5.

Description

Method, equipment and storage medium for predicting oxygen release difficulty of lithium-rich manganese-based positive electrode material Technical Field The application relates to the technical field of new energy, in particular to a method, equipment and a storage medium for predicting oxygen release difficulty of a lithium-rich manganese-based positive electrode material. Background With the development of new energy automobiles and other energy storage facilities, the energy density requirements of lithium ion batteries are higher and higher, and compared with the traditional ternary positive electrode material, the lithium-rich manganese-based positive electrode material is widely paid attention to because of the theoretical capacity of the lithium-rich manganese-based positive electrode material exceeding 300 mAh/g. However, the most rapidly developed research of the lithium-rich manganese-based positive electrode material at present only completes pilot scale, one of the reasons for preventing industrialization of the lithium-rich manganese-based positive electrode material is the problem of oxygen release under high voltage, the oxygen release of the lithium-rich manganese-based positive electrode material under high voltage can seriously affect the safety and the cycle life of a battery, and the electrochemical mechanism of the lithium-rich manganese-based positive electrode material needs to be deeply researched and the corresponding performance improvement is made. While the internal structure of the material is difficult to observe and make mechanism explanation in the traditional experimental study, the first sex principle calculation can reveal the formation mechanism of the intrinsic performance of the material from the atomic scale, predict the physical and chemical properties of the material, guide the experiment and greatly improve the research efficiency. However, in the current calculation, the stability of oxygen is often studied by calculating the oxygen vacancy formation energy, however, the research finds that the release of oxygen is often accompanied by the migration of transition metal, so the migration of transition metal in the layer or between layers affects the release of oxygen. In the existing calculation method, the influence of transition metal migration is not considered, the result of predicting the difficulty in oxygen release of the lithium-rich manganese-based positive electrode material is not accurate enough, and the mechanism of oxygen generation is difficult to understand. Disclosure of Invention The application aims to provide a method, equipment and a storage medium for predicting the oxygen release difficulty of a lithium-rich manganese-based positive electrode material, and aims to solve the problems that the effect of transition metal migration is not considered in the existing calculation method, the result of predicting the oxygen release difficulty of the lithium-rich manganese-based positive electrode material is not accurate enough, and the oxygen generation mechanism is difficult to understand. In order to achieve the above object, the present application provides a method for predicting oxygen release difficulty of a lithium-rich manganese-based cathode material, comprising: Carrying out lithium removal simulation charging process on the initial unit cell structure of the lithium-rich manganese-based anode material and generating lithium vacancies to obtain a first configuration; migrating transition metal ions to the lithium vacancies and generating oxygen to obtain a second configuration; Calculating a migration energy barrier of the transition metal ion according to the first configuration and the second configuration; And predicting the oxygen release difficulty of the lithium-rich manganese-based positive electrode material according to the migration energy barrier of the transition metal ions. Preferably, the initial unit cell structure is built according to the chemical formula of the lithium-rich manganese-based positive electrode material, the space group of the lithium-rich manganese-based positive electrode material is C2/m, the chemical formula of the lithium-rich manganese-based positive electrode material is xLi 2MnO3·(1-x)LiTMO2 or Li 1+xTMyMn1-x-yO2, wherein TM is transition metal, 0< x <1,0< y <1, and the initial unit cell structure is the configuration with the lowest free energy obtained after structural optimization under the chemical formula. Preferably, the performing a delithiation simulated charging process on the initial unit cell structure of the lithium-rich manganese-based cathode material and generating lithium vacancies to obtain a first configuration includes: And during each lithium removal, carrying out lithium removal on each lithium ion of the initial unit cell structure, comparing configuration energy after each lithium ion is respectively removed, taking the configuration with the lowest free energy as the most stab