Carbon-Coated Lithium-Rich Oxide for Conductive Lithium Compensation
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Solution Overview
Problem
Existing lithium supplementation methods for lithium-ion batteries have high environmental requirements and risks, and they are prone to accidents, leading to irreversible capacity loss and reduced energy density.
Innovation Solution
A carbon-coated lithium-rich oxide composite material is prepared by mixing an iron or cobalt source with a lithium source, sintering, crushing, and then coating with carbon, which enhances conductivity and provides active lithium for the positive electrode material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If existing lithium supplementation methods are used, then active lithium can be compensated, but environmental requirements are high and safety risks increase
Solution Approach 1:
The patent introduces lithium-rich oxide as an intermediary substance that indirectly supplements active lithium to the positive electrode. Instead of directly adding lithium powder or solutions that require strict environmental controls, the lithium-rich oxide serves as a stable intermediate that releases lithium during battery operation, thereby compensating for lithium loss while eliminating the need for hazardous handling procedures
Solution Approach 2:
The patent employs lithium-rich oxide as a sacrificial material that is intentionally designed to be consumed during the battery's initial cycles. This disposable approach allows the material to release its lithium content to replenish the positive electrode, after which the depleted lithium-rich oxide is simply replaced in subsequent battery assemblies, avoiding the need for complex recovery and recycling processes
2Quantity of substance
If lithium-rich oxide is added to positive electrode material, then lithium supplementation is achieved, but conductivity is insufficient
Solution Approach 1:
The patent creates a composite structure by coating lithium-rich oxide particles with conductive carbon material. This composite approach combines the lithium-supplementing capability of lithium-rich oxide with the excellent electrical conductivity of carbon, resulting in a material that simultaneously provides both functions. The carbon coating forms a conductive network around the lithium-rich oxide core, ensuring efficient electron transport while the core releases lithium ions
Solution Approach 2:
The patent applies different material properties to different regions of the composite structure. The core region (lithium-rich oxide) is optimized for lithium ion release, while the surface region (carbon coating) is optimized for electrical conductivity. This spatial differentiation of material properties allows each component to perform its specialized function effectively, with the carbon shell providing electron pathways while the oxide core provides lithium reservoir
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The carbon-coated lithium-rich oxide composite material improves the energy density of lithium-ion batteries by compensating for lost active lithium during the initial charge-discharge process, with improved electrochemical properties and stability.
Implementation Method 1
mixing an iron source or a cobalt source with a lithium source, and sintering to obtain a lithium-rich oxide Li5FeO4 or Li6CoO4
Implementation Method 2
mixing the lithium-rich oxide crushed in the step (2) with a carbon source, and sintering to obtain the carbon-coated lithium-rich oxide composite material
Data Source
AI summary
The present disclosure relates to the technical field of positive electrode lithium-supplementing additives of the lithium battery, and discloses a carbon-coated lithium-rich oxide composite material and a preparation method thereof. The method comprises the following steps: (1) mixing an iron source or a cobalt source with a lithium source, and sintering to obtain a lithium-rich oxide Li5FeO4 or Li6CoO4; wherein, a molar ratio of the lithium source to the iron source is 5-25:1, and a molar ratio of the lithium source to the cobalt source is 6-30:1; (2) crushing the lithium-rich oxide obtained in the step (1); and (3) mixing the lithium-rich oxide crushed in the step (2) with a carbon source, and sintering to obtain the carbon-coated lithium-rich oxide composite material. The carbon-coated lithium-rich oxide composite material prepared by the method of the present disclosure overcomes the insufficient conductivity of lithium-rich materials, and has good electrochemical properties, which is capable of effectively compensating for active lithium lost during the initial charge-discharge process of the lithium battery.