ZrP2O7 Coated Lithium Composite Oxide Cathode
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Solution Overview
Problem
Lithium batteries face challenges in achieving high energy density and long lifespan due to the limitations of existing cathode active materials, such as LiCoO2, which exhibit low reversible capacity and structural instability during charging and discharging.
Innovation Solution
A composite cathode active material is developed, comprising a lithium composite oxide with a coating layer containing ZrP2O7 and LiZr2(PO4)3, formed by reacting an acid-treated zirconium precursor and phosphorus precursor with the lithium composite oxide, enhancing electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If LiCoO2 is used as cathode active material, then high voltage is achieved, but reversible capacity is low and structural stability is poor
Solution Approach 1:
The patent applies composite materials by forming a coating layer containing ZrP2O7 and LiZr2(PO4)3 on the LiCoO2 cathode active material. This composite structure combines the high voltage properties of LiCoO2 with the structural stability provided by the zirconium phosphate coating, resolving the contradiction between achieving high voltage and maintaining structural stability during charging and discharging cycles.
Solution Approach 2:
The patent applies local quality by creating a coating layer with specific local properties (ZrP2O7 and LiZr2(PO4)3 composition) on the surface of the LiCoO2 particles. This localized modification maintains the bulk high voltage characteristics of LiCoO2 while providing local structural stability at the particle surface and interface regions where structural degradation typically occurs.
2Power
If LiCoO2 is used as cathode active material, then high voltage is achieved, but reversible capacity is low
Solution Approach 1:
The composite coating structure enables the cathode to achieve both high voltage (from LiCoO2) and enhanced reversible capacity (through the coating's contribution to capacity and stability). The ZrP2O7 and LiZr2(PO4)3 coating provides additional lithium insertion/extraction sites while maintaining structural integrity, thereby increasing overall reversible capacity without sacrificing voltage.
3Ease of manufacture
If conventional cathode materials are used, then manufacturing is simple, but electrochemical performance is limited
Solution Approach 1:
The patent applies preliminary action by pre-treating the zirconium precursor with acid before forming the coating layer on LiCoO2. This preliminary treatment enhances the reactivity and coating formation efficiency, allowing the complex composite coating to be formed through a relatively simple one-step heat treatment process, thus maintaining ease of manufacture while achieving superior electrochemical performance.
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 composite cathode active material improves capacity retention rate and overall electrochemical performance, suitable for high-energy density applications and extended cycle life in lithium batteries.
Implementation Method 1
a coating layer disposed on at least a portion of the lithium composite oxide and including a composite including ZrP2O7 and LiZr2(PO4)3, wherein the composite including ZrP2O7 and LiZr2(PO4)3 is a reaction product of an acid-treated zirconium precursor, a phosphorus precursor, and the lithium composite oxide
Data Source
AI summary
A composite cathode active material for a lithium battery, the composite cathode active material including: a lithium composite oxide; and a coating layer disposed on at least a portion of the lithium composite oxide and including a composite including ZrP2O7 and LiZr2(PO4)3, wherein the composite including ZrP2O7 and LiZr2(PO4)3 is a reaction product of an acid treated a zirconium precursor, a phosphorus precursor, and the lithium composite oxide.