Lithium Battery Cathode Gradient and Anode Composite
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Solution Overview
Problem
Lithium secondary batteries face challenges in achieving high capacity, energy density, and stability, particularly at high temperatures, due to limitations in cathode and anode active materials.
Innovation Solution
The battery incorporates lithium metal oxide particles with a concentration gradient region and an anode containing a silicon-based and carbon-based active material, where the carbon content is higher than silicon, to enhance operational and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional cathode and anode active materials are used, then the battery can operate, but the capacity and energy density are insufficient
Solution Approach 1:
The cathode active material employs a concentration gradient structure where the composition varies spatially from the particle center to the surface. The central region contains a first metal element (e.g., nickel) providing high capacity, while the outer region contains a second metal element (e.g., manganese) providing stability. This local differentiation resolves the contradiction by assigning different functional properties to different regions of the same particle.
Solution Approach 2:
The cathode active material is constructed as a composite with multiple metal elements distributed in a concentration gradient pattern. This composite structure combines the high-capacity characteristics of nickel-rich regions with the stability characteristics of manganese-rich regions, simultaneously achieving both high capacity and high-temperature stability.
2Quantity of substance
If the anode contains only carbon-based active material, then the structure is stable, but the energy density is limited
Solution Approach 1:
The anode active material merges silicon-based active material with carbon-based active material in a composite structure. The silicon component provides high energy density through lithium alloying, while the carbon component provides structural stability and conductivity. This combination resolves the contradiction between energy density and structural stability.
3Quantity of substance
If the anode contains high silicon content, then the energy density increases, but the mechanical stability deteriorates
Solution Approach 1:
The anode employs a composite structure where silicon-based material is distributed within a carbon-based matrix. The carbon phase provides mechanical strength and structural integrity, while the silicon phase contributes to high energy density. This local distribution resolves the contradiction by containing silicon in regions that benefit from its high capacity while being supported by the stable carbon framework.
Data Source
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AI summary
A lithium secondary battery according to an embodiment of the present invention comprises a cathode and an anode. The cathode comprises lithium metal oxide particles that contains lithium and metal elements. The lithium metal oxide particles have a concentration gradient region formed in at least one region between a center and a surface. A concentration of at least one of the metal elements is changed in the concentration gradient region. The anode comprises an anode active material that contains a silicon-based active material and a carbon-based active material. A content of the carbon-based active material in the anode active material is greater than a content of the silicon-based active material.