Lithium Cell Electrode Material Stabilization via Redox Doping
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Solution Overview
Problem
High-energy lithium-ion batteries, particularly HE-NCM, suffer from significant voltage and capacity fade over time, making them unsuitable for long-term use in electric vehicles despite their high initial performance.
Innovation Solution
An electrode material for lithium-ion batteries is developed, comprising a first lithiatable transition metal oxide and a second doped transition metal oxide with a redox-active element, which stabilizes the structure by reducing oxygen defects and facilitating transition metal migration, thereby extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-energy NCM materials are used to achieve high start voltage and energy density, then the initial performance is improved, but significant voltage fade and capacity fade occur during service life
Solution Approach 1:
The patent modifies the chemical composition parameters of the NCM material by introducing a dual-doping strategy: redox-inactive elements (Mg, Sn) at 0.5-5 mol% to stabilize structure, and redox-active elements (Ni, Co, Mn) at 0.1-5 mol% to maintain electrochemical activity. This parameter optimization resolves the contradiction between high initial voltage and long-term stability
Solution Approach 2:
The patent creates a composite doped NCM material combining multiple elements (Ni, Co, Mn, Mg, Sn) in a unified crystal structure. The composite structure integrates the structural stabilization function of redox-inactive dopants with the electrochemical activity of redox-active dopants, simultaneously achieving high start voltage and reduced voltage fade
2Reliability
If redox-inactive elements (Mg, Sn) are introduced to stabilize the material structure, then voltage fade is reduced, but start capacity and start voltage are lost
Solution Approach 1:
The patent precisely controls the doping concentration parameters: redox-inactive elements (Mg, Sn) are limited to 0.5-5 mol% for structural stabilization, while redox-active elements (Ni, Co, Mn) are added at 0.1-5 mol% to restore electrochemical activity. This optimized parameter balance resolves the contradiction between structural stability and capacity
Solution Approach 2:
The patent applies different doping elements to different functional requirements within the same material: redox-inactive elements (Mg, Sn) provide local structural stabilization at specific lattice sites, while redox-active elements (Ni, Co, Mn) provide local electrochemical activity. This spatial-functional differentiation resolves the contradiction between stability 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 electrode material maintains 97.5% voltage and capacity retention after 3,000 charging and discharging cycles, significantly improving the service life of lithium-ion batteries.
Implementation Method 1
at least one redox-active element, in particular at least one of Ni(II), Co(II), Mn(III), Mo(IV), W(IV), Nb(IV), which changes its oxidation stage during activation
Data Source
AI summary
An electrode material for an electrochemical energy store, in particular for a lithium cell, includes at least one first lithiatable active material, which is based on a transition metal oxide, and at least one second lithiatable active material, which is based on a doped transition metal oxide, the doped transition metal oxide of the second lithiatable active material being doped with at least one redox-active element. Also described is a method for manufacturing an electrode of this type.