High-Entropy Doped Cathode Materials for Lithium-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high energy density, long life cycle, and reduced reliance on toxic cobalt, with existing materials experiencing issues like rapid voltage fading, oxygen loss, and structural instability during high charge voltages.
Innovation Solution
A composition for a lithium ion battery cathode using a high-entropy doping strategy with multiple dopants such as LiNi0.33Mn0.03Ti0.02Mg0.02Mo0.02Nb0.01O2, which stabilizes the material by mitigating oxygen loss, reducing lattice expansion, and suppressing cation mixing, thereby enhancing structural and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high nickel content materials (e.g., LiNi0.8Mn0.1Co0.1O2) are used to achieve high capacity and energy density, then battery energy density is improved, but structural stability and oxygen retention deteriorate due to H2-H3 phase transition and stacking faults
Solution Approach 1:
The patent applies local quality by introducing multiple dopants (Ti, Mg, Mo, Nb) at specific concentrations (0.01-0.05 atomic ratio) to create localized structural modifications in the cathode material. These dopants are strategically positioned to stabilize specific crystallographic regions and suppress phase transitions locally, thereby maintaining overall structural stability while preserving high nickel content for energy density.
Solution Approach 2:
The patent creates a composite cathode material by combining high nickel content base material (LiNi0.8Mn0.1Co0.1O2) with multiple dopant elements (Ti, Mg, Mo, Nb). This composite approach leverages the high capacity of nickel while the dopants provide structural stabilization, oxygen retention, and suppression of detrimental phase transitions, achieving both high energy density and improved stability.
2Quantity of substance
If cobalt is eliminated from the cathode chemistry to reduce cost and toxicity, then material cost and environmental impact are improved, but oxygen retention and structural stability deteriorate
Solution Approach 1:
The patent extracts cobalt from the traditional NMC cathode chemistry, developing cobalt-free compositions such as LiNi0.96Ti0.02Mg0.02O2 and LiNi0.8Mn0.13Ti0.02Mg0.02Mo0.02Nb0.01O2. By removing cobalt entirely and replacing it with alternative dopants, the patent achieves both cost reduction and improved oxygen retention through the synergistic effects of multiple dopants.
Solution Approach 2:
The patent changes the chemical composition parameters by eliminating cobalt and introducing multiple dopants at optimized concentrations. This parameter change transforms the cathode material from cobalt-dependent to dopant-stabilized, achieving improved oxygen retention and structural stability without relying on toxic and expensive cobalt.
3Device complexity
If single dopant (e.g., Ti or Mg) is used to stabilize the cathode material, then manufacturing complexity is reduced, but oxygen retention and structural stability are insufficient
Solution Approach 1:
The patent merges multiple dopant elements (Ti, Mg, Mo, Nb) into a unified doping strategy, where each dopant contributes specific functions: Ti and Mg for structural stabilization, Mo and Nb for oxygen retention. This combination creates a synergistic effect that achieves superior oxygen retention and structural stability compared to single dopant approaches, while maintaining manageable manufacturing complexity through standardized synthesis procedures.
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 high-entropy doped cathode materials exhibit improved capacity retention, thermal stability, and extended life cycle, with reduced strain and oxygen loss, breaking the trade-off between capacity and stability, and eliminating the need for cobalt.
Implementation Method 1
stabilizes the material by mitigating oxygen loss, reducing lattice expansion, and suppressing cation mixing
Implementation Method 2
A composition for a lithium ion battery cathode using a high-entropy doping strategy with multiple dopants such as LiNi0.33Mn0.03Ti0.02Mg0.02Mo0.02Nb0.01O2, which stabilizes the material by mitigating oxygen loss, reducing lattice expansion
Implementation Method 3
high-entropy doping strategy with multiple dopants... suppressing cation mixing, thereby enhancing structural and thermal stability
Implementation Method 4
a composition for use in a cathode for a lithium ion battery
Data Source
AI summary
The present invention features a new way of doping layered cathode materials in lithium ion batteries. Using a “high entropy” doping strategy, more than four impurity elements can be introduced to the host materials. The present invention applies this high entropy doping strategy to a high nickel content layered oxide material and a lithium-manganese rich material. This new high entropy doping strategy allows the layered oxide materials used in the positive electrode of lithium ion battery to achieve high energy density, long life cycle and reduced reliance on the expensive and toxic cobalt, all of which are desired attributes for improving the performance of lithium ion batteries and reducing their cost.