High-Loading Cathode Surface Chemistry for Uniform Li-Ion Battery Reactions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional non-aqueous electrolyte secondary batteries face challenges in maintaining high volumetric energy density while improving output and cycle characteristics, particularly in larger battery sizes, due to uneven reaction distribution and increased internal resistance.
Innovation Solution
Incorporating a lithium-containing composite oxide with a surface-modified layer containing Ca and Sr, along with elements like W, Mo, Ti, Si, Nb, and Zr, and setting a basis weight of the positive electrode mixture layer to greater than or equal to 250 g/m2, enhances reaction uniformity and reduces internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery size is increased to improve volumetric energy density, then the energy storage capacity increases, but the output characteristics and cycle characteristics deteriorate due to uneven reaction distribution and increased internal resistance
Solution Approach 1:
The patent applies local quality by creating a surface-modified layer on the lithium-containing composite oxide particles. This modified layer has different composition and properties from the core particles, with specific elements (Ca, Sr, and at least one of W, Mo, Ti, Si, Nb, Zr) concentrated at the particle surfaces. This local modification improves reaction uniformity and reduces internal resistance in larger batteries, resolving the contradiction between energy density and output characteristics.
Solution Approach 2:
The patent uses composite materials by combining lithium-containing composite oxide particles with a surface-modified layer containing specific elements. The core-shell structure with the modified layer creates a composite material that maintains high capacity while improving electrochemical performance. The composite structure addresses the internal resistance issue in larger batteries without sacrificing volumetric energy density.
2Reliability
If a surface-modified layer containing Ca, Sr, and elements like W, Mo, Ti, Si, Nb, Zr is incorporated into the positive electrode active material, then reaction uniformity improves and internal resistance decreases, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the surface composition of the active material particles. Specifically, it controls the presence of Ca, Sr, and at least one of W, Mo, Ti, Si, Nb, Zr in the surface-modified layer. By adjusting these compositional parameters, the patent achieves improved reaction uniformity and reduced internal resistance while managing the complexity through targeted elemental additions rather than complex structural designs.
Data Source
AI summary
A non-aqueous electrolyte secondary battery comprises an electrode body and an exterior body, and has a volumetric energy density of 600 Wh/L or more. The positive electrode includes: a positive electrode core body; and a positive electrode mixture layer containing a positive electrode active material. The positive electrode active material contains: a lithium-containing composite oxide having a layered rock-salt structure; and a surface modification layer that is present on particle surfaces of the composite oxide. The surface modification layer contains: at least one element of Ca and Sr; and at least one element selected from the group consisting of W, Mo, Ti, Si, Nb, and Zr. The positive electrode mixture layer has a base weight amount of 250 g/m2 or more. At least three positive electrode leads are connected to the positive electrode.