Copper-Doped Li-Rich Cathode Material for Capacity Retention
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Solution Overview
Problem
Existing lithium-ion battery cathode materials face challenges such as decreased capacity with charging cycles, low initial coulombic efficiency, poor capacity retention, and instability during cycling.
Innovation Solution
A lithium-rich manganese-rich layered oxide material doped with copper, specifically a composite oxide of formula LiaMa′MnbNixCoyCuzO2, is developed, which maintains high discharge capacity and capacity retention even with high copper content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-rich manganese-based layered oxide materials are used as cathode materials, then high discharge capacity can be achieved, but initial coulombic efficiency is low and capacity retention is poor
Solution Approach 1:
The patent applies parameter changes by precisely controlling the stoichiometric ratios of metals in the spinel structure (formula: Li2-xMn1-y-zAlxO4) and adjusting the doping levels of Al, Ru, Mg, Ti, Zn, Zr, and Cu to optimize both discharge capacity and capacity retention. By varying compositional parameters within specific ranges, the material achieves high capacity while maintaining reliability over cycling.
Solution Approach 2:
The patent employs composite materials through multi-element doping in the spinel structure, combining Mn-rich base material with multiple dopants (Al, Ru, Mg, Ti, Zn, Zr, Cu) to create a composite cathode material that synergistically improves both discharge capacity and capacity retention, resolving the contradiction between high capacity and reliable performance.
2Quantity of substance
If lithium-rich manganese-based layered oxide materials are used, then high discharge capacity is achieved, but structural instability and poor thermal characteristics occur
Solution Approach 1:
The patent uses parameter changes by adjusting the metal ratios and doping concentrations in the spinel structure to stabilize the crystal structure while maintaining high discharge capacity. The controlled composition prevents Jahn-Teller distortion and structural degradation during cycling.
Solution Approach 2:
The patent introduces dopant elements as intermediaries in the spinel structure that act as structural stabilizers, mediating between the high-capacity requirement and structural stability. These dopants reinforce the lattice structure and prevent degradation while allowing high lithium insertion/extraction.
3Reliability
If copper doping is increased to improve capacity retention, then capacity retention improves, but discharge capacity decreases
Solution Approach 1:
The patent applies parameter changes by precisely optimizing the copper doping level within a specific range in the spinel structure, balancing the competing effects of capacity retention improvement and capacity maintenance. The controlled copper content provides stability without excessive capacity loss.
Solution Approach 2:
The patent uses local quality by strategically placing copper dopants at specific sites in the spinel structure where they provide maximum stabilizing effect with minimum impact on discharge capacity. The localized doping approach optimizes the trade-off between retention and capacity.
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 copper-doped lithium-rich manganese-rich layered oxide material exhibits higher discharge capacity, improved capacity retention, and high initial coulombic efficiency, addressing the limitations of previous materials.
Implementation Method 1
The cathode is generally made of metal oxides which undergo reversible RedOx reactions during the charging and discharging processes
Data Source
AI summary
The present invention relates to an electrode material consisting of a lithium-rich manganese rich oxide compound doped with copper particularly useful as cathode material in lithium-ion batteries of formula (I)LiaMa′MnbNixCoyCuzO2 (I)wherein:M is selected from Na, Li, K and mixtures thereof;1.05≤a+a′≤1.3;0.55≤b≤0.70;0.15≤x≤0.30;0.025≤y≤0.125;and0.05<z≤0.125.