LMR Cathode Composition Balancing Voltage Stability and Energy Density

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Solution Overview

Problem

Lithium and manganese-rich (LMR) positive electrode active materials face issues such as voltage decay during cycling, poor rate capability, and low volumetric energy density, hindering their commercialization.

Innovation Solution

A positive electrode active material composition represented by Li(1.333-0.667x-y)Mn(0.667-0.333x)NixMyO2 or Li(4/3-2/3x-y)Mn(2/3-1/3x)NixMyO2, where M is Co or Cr, with 0.13<x<0.5 and 0<y<0.333, is developed to mitigate these issues by incorporating a higher Mn+3 oxidation state and lower Li content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LMR composition with higher Mn content and lower Li content is used, then voltage decay during cycling is mitigated and rate capability is improved, but volumetric energy density decreases

Engineering Contradiction:

Improvecycle performanceVSAvoidvolumetric energy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent optimizes the stoichiometric parameters of the LMR composition by precisely controlling the ratios of Li, Mn, Ni, and M elements according to formula (1), where x and y are within specific ranges. This parameter optimization achieves a balance between Mn content (for cycle performance) and Li content (for energy density), resolving the contradiction between reliability and quantity of substance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite cathode material system combining LMR composition with specific additives or coatings (implied by the complex formulation with multiple elements Ni, Co, Cr). This composite approach allows the base LMR material to provide high capacity while the composite structure mitigates voltage decay and maintains volumetric energy density

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If LMR composition with higher Mn content is used, then gravimetric energy density is improved, but rate capability deteriorates

Engineering Contradiction:

Improvegravimetric energy densityVSAvoidrate capability

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent introduces element M (Co or Cr) at specific positions in the crystal structure to locally improve electronic conductivity and ion transport properties. This local quality enhancement at strategic sites within the LMR structure enables faster reaction rates while maintaining the overall high Mn content for gravimetric energy density

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If LMR composition with lower Li content is used, then voltage decay during cycling is reduced, but cycle performance worsens

Engineering Contradiction:

Improvevoltage stabilityVSAvoidcycle life

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The patent introduces element M (Co or Cr) as an intermediary element that mediates between the Li-rich and Mn-rich phases. This intermediary element stabilizes the crystal structure during cycling, preventing severe voltage decay while simultaneously maintaining long cycle life by reducing structural degradation

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12597606B2Lithium and manganese rich positive active material compositions

Publication Date: 2026.04.07 FORD GLOBAL TECH LLC

AI summary

A positive electrode active material includes a compound represented by formula 1:Li(1.333-0.667x-y)Mn(0.667-0.333x)NixMyO2 or Li(4/3-2/3x-y)Mn(2/3-1/3x)NixMyO2 (1)wherein,M is Co, Cr, or a combination thereof,0.13<x<0.5; and0<y<0.333.