Cathode Active Material Surface Doping for High-Ni Battery Cycling
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries using lithium-containing composite oxides with Ni as a main component face challenges with reduced initial charge-discharge efficiency and battery capacity due to charge and discharge cycles.
Innovation Solution
A positive electrode active material is developed, comprising a lithium-containing composite oxide with a layered rock-salt structure, represented by LixNiaCobMncM1dO2-y, where M1 includes elements like W, Mg, Mo, Nb, Ti, Si, Al, and Zr. This material includes secondary particles formed by aggregating primary particles, with a sulfonate compound, Ca, Sr, W, Mo, Ti, Si, Nb, and Zr present on the surfaces or interfaces, enhancing charge-discharge efficiency and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium-containing composite oxide with Ni as main component is used, then energy density is improved, but initial charge-discharge efficiency and battery capacity are reduced
Solution Approach 1:
The patent applies local quality by creating a dual-component surface modification: (1) sulfonate compounds are introduced on particle surfaces to improve initial charge-discharge efficiency, and (2) M1 elements (W, Mo, Ti, Si, Nb, Zr) are incorporated in the bulk lattice to maintain structural stability during cycling. This localized functional differentiation resolves the contradiction between high Ni content for energy density and surface effects for efficiency.
Solution Approach 2:
The patent uses composite materials by combining lithium-containing composite oxide with Ni (0.75≤a≤0.95) for high energy density with surface-modified compounds containing sulfonate groups and M1 elements. This composite structure allows the core material to provide high capacity while the surface layer provides improved charge-discharge efficiency and cycle stability.
2Use of energy by moving object
If lithium-containing composite oxide with Ni as main component is used, then energy density is improved, but battery capacity is reduced due to charge and discharge
Solution Approach 1:
The patent applies preliminary action by pre-introducing sulfonate compounds and M1 elements onto/into the lithium-containing composite oxide particles before battery assembly. This preliminary surface modification creates a protective interface that prevents capacity degradation during subsequent charge-discharge cycles, allowing the high-Ni material to maintain its energy density advantage while improving duration of action.
3Reliability
If sulfonate compound and M1 elements are introduced on particle surfaces, then initial charge-discharge efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into a unified surface treatment process: the sulfonate compound introduction and M1 element incorporation are combined in a single surface modification step. This merging approach improves initial charge-discharge efficiency while minimizing manufacturing complexity by avoiding separate processing steps for each functional component.
Data Source
AI summary
A positive electrode active material which is to be included in this nonaqueous electrolyte secondary battery and contains a lithium-containing complex oxide having a prescribed composition which has a layered evaporitic structure, wherein: the lithium-containing complex oxide contains secondary particles formed by clumping primary particles with one another; and a sulfonic acid compound represented by general formula I, one or more types of element selected from Ca and Sr, and one or more types of element selected from W, Mo, Ti, Si, Nb and Zr are present on the surface of the secondary particles or at the interface between the primary particles. (In the formula, A is a Group 1 element or a Group 2 element, R is a hydrocarbon group, and n is 1 or 2.)