High-Nickel Cathode Material With Controlled Oxygen Defects
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Solution Overview
Problem
Current lithium-ion battery positive electrode materials, such as lithium iron phosphate and low nickel ternary materials, fail to meet energy density requirements and suffer from rapid cycle performance deterioration due to increased Li/Ni mixing and oxygen defects, limiting their use in traction batteries.
Innovation Solution
A high nickel ternary positive electrode material with controlled oxygen defect levels (1.77≤OD1≤1.90 and/or 0.69≤OD2≤0.74) is developed by adjusting synthesis processes like precursor preparation and sintering conditions, combined with a coating layer to stabilize the crystal structure and reduce Li/Ni mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel content is increased in high nickel ternary positive electrode material to improve energy density, then energy density is improved, but Li/Ni mixing increases and oxygen defects increase causing rapid cycle performance deterioration
Solution Approach 1:
The patent applies parameter changes by precisely controlling the oxygen defect level within the range of 1.77≤OD1≤1.90 and 0.69≤OD2≤0.74, and adjusting synthesis parameters including precursor preparation, sintering temperature (800-950℃), sintering time (5-15h), and oxygen concentration (20-40%). These parameter optimizations resolve the contradiction by maintaining high nickel content for energy density while controlling oxygen defects to prevent cycle performance deterioration
Solution Approach 2:
The patent employs composite materials by combining high nickel ternary material with a coating layer containing one or more of Al2O3, SiO2, TiO2, ZrO2, MgO, or WO3. This composite structure allows the core material to provide high energy density while the coating layer protects against oxygen defects and Li/Ni mixing, thereby improving cycle performance without sacrificing energy density
2Reliability
If conventional lithium iron phosphate or low nickel ternary materials are used to maintain stable cycle performance, then cycle performance is stable, but energy density requirements of traction batteries cannot be met
Solution Approach 1:
The patent transforms conventional low-nickel materials into high-performance materials by changing the nickel content parameter to 0.6≤Ni≤0.95 and precisely controlling oxygen defect levels (1.77≤OD1≤1.90, 0.69≤OD2≤0.74). This parameter transformation enables the material to achieve both high energy density and stable cycle performance, overcoming the limitations of conventional materials
3Reliability
If doping and coating methods are used to improve cycle performance of ternary positive electrode material, then cycle performance is improved to some extent, but there is still a gap to meet market demand
Solution Approach 1:
The patent achieves superior cycle performance by optimizing multiple parameters simultaneously: nickel content (0.6≤Ni≤0.95), oxygen defect levels (1.77≤OD1≤1.90, 0.69≤OD2≤0.74), sintering temperature (800-950℃), and coating composition. This multi-parameter optimization produces material with exceptional cycle stability that exceeds conventional improvement methods and meets stringent market demands for traction batteries
Solution Approach 2:
The patent creates a composite structure combining high nickel ternary material core with protective coating layer (Al2O3, SiO2, TiO2, ZrO2, MgO, or WO3). This composite design provides synergistic effects where the core delivers high capacity and the coating ensures long-term stability, achieving performance levels that satisfy market requirements for both energy density and cycle life
Data Source
AI summary
This disclosure relates to the electrochemical field, and in particular, to a positive electrode material and a preparation method and usage thereof. The positive electrode material of this disclosure includes a substrate, where a general formula of the substrate is LixNiyCozMkMepOrAm, where 0.95≤x≤1.05, 0.5≤y≤1, 0≤z≤1, 0≤k≤1, 0≤p≤0.1, 1≤r≤5.2, 0≤m≤2, m+r≤2, Mis selected from one or more of Mn and Al, Me is selected from one or more of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, and Nb, and A is selected from one or more of N, F, S, and Cl; and an oxygen defect level of the positive electrode material satisfies at least one of condition (1) or condition (2): (1) 1.77≤OD1≤1.90; or (2) 0.69≤OD2≤0.74.