Disordered Rocksalt Cathode Composition for Higher Conductivity
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Solution Overview
Problem
Lithium-excess disordered rocksalt cathode materials exhibit high energy capacity but are limited by low electrical conductivity, requiring high amounts of carbon-based conductive materials, which reduces energy density and makes practical implementation challenging.
Innovation Solution
A method to manufacture a disordered rocksalt-cathode active material by optimizing the selection of redox center and transition metal composition, using Monte Carlo and Markov Chain Monte Carlo simulations to determine the proportion of accessible redox centers within the percolating network, thereby enhancing electrical conductivity and reducing the need for carbon-based conductive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium-excess disordered rocksalt cathode material is used to achieve high energy capacity, then energy capacity is improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent changes the compositional parameters of the cathode material by incorporating specific transition metals (Ti, Zr, V, Nb, Sn, Mo) in controlled amounts alongside lithium-excess formulation. This parameter optimization enables the material to achieve both high energy capacity and improved electrical conductivity without requiring excessive carbon additives
Solution Approach 2:
The patent creates a composite cathode material structure that integrates lithium-excess disordered rocksalt with carefully selected transition metals. This composite approach allows the material to benefit from both the high capacity of lithium-excess formulation and the conductivity enhancement from transition metal incorporation
2Reliability
If carbon-based conductive material is increased to improve electrical conductivity, then electrical conductivity is improved, but energy density deteriorates
Solution Approach 1:
The patent extracts the conductivity enhancement function from external carbon-based conductive additives and transfers it to the cathode material itself through transition metal incorporation. This eliminates the need for excessive carbon black (reducing from 10-20% to minimal amounts), thereby preserving energy density while maintaining electrical conductivity
3Reliability
If transition metal composition is optimized to improve electrical conductivity, then electrical conductivity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs transition metals that serve multiple functions simultaneously: they enhance electrical conductivity, contribute to energy capacity through redox reactions, and stabilize the crystal structure. This multi-functionality reduces the need for separate additives and simplifies the overall manufacturing process despite the compositional optimization
Data Source
AI summary
There is provided a method of manufacturing a disordered rocksalt-cathode active material of Formula 1:Li0.4+xM1yM2zO2−kFk (1)Wherein, 0<x≤1.6, 0≤z≤1, 0≤k≤0.660<y≤1 and (x+y+z)≤1.6, and wherein M1 is a redox center selected from Mn, Ni, V, Co, Fe, Ir, Cr, Ru, Mo, and combinations thereof, and M2 is a d0 transitional metal selected from Ti, Zr, V, Nb, Sn, Mo and combinations thereof. The value of y is determined for a species of M1 based on a selection of the other parameters in order to maximize the electrical conductivity. Mathematical simulations that leverage the polaron energy barrier are used to determine the percolation probability and the accessibility of M1 in the percolation network. This allows to select for values of y to obtain a proportion of accessible M1 of at least 90% to improve electrical conductivity and manufacture the active material accordingly.