Fluorine-Doped LMR Cathode Composition for Voltage Decay Control
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Solution Overview
Problem
Current Lithium Manganese Rich (LMR) positive electrode active materials face issues with voltage decay during cycling, rate capability, and cycle performance, as well as lower volumetric energy density.
Innovation Solution
The composition of the LMR material is optimized by adjusting the lithium, nickel, cobalt, and chromium content, with controlled average oxidation states and fluorine doping, to enhance electronic and ionic conductivity, and improve cycle performance and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LMR material composition is optimized with adjusted lithium, nickel, cobalt, and chromium content along with fluorine doping, then electronic and ionic conductivity is enhanced and cycle performance is improved, but manufacturing precision requirements increase due to strict compositional control parameters
Solution Approach 1:
The patent applies parameter changes by optimizing specific compositional parameters (lithium content 1.05-1.15, nickel content 0.30-0.40, chromium content 0.01-0.05, fluorine doping 0.02-0.08) to achieve improved cycle performance and conductivity while maintaining manufacturability through defined parameter ranges
Solution Approach 2:
The patent uses composite materials by combining multiple elements (lithium, manganese, nickel, cobalt, chromium, fluorine) in specific proportions to create a composite cathode material that achieves synergistic effects, improving both conductivity and cycle performance while managing manufacturing complexity
2Use of energy by moving object
If LMR material is used to achieve high gravimetric energy density, then energy capacity is improved, but volumetric energy density is reduced
Solution Approach 1:
The patent addresses the volumetric energy density issue by optimizing the lithium content parameter (1.05-1.15) and fluorine doping level (0.02-0.08) to enhance material density and packing efficiency, thereby improving volumetric energy density while preserving the high gravimetric energy density advantage of LMR materials
3Use of energy by moving object
If conventional LMR material composition is used, then high gravimetric energy density is achieved, but voltage decay during cycling occurs
Solution Approach 1:
The patent uses composite materials by incorporating chromium (0.01-0.05) as a stabilizing element alongside nickel and fluorine doping to create a composite structure that maintains voltage stability during cycling while preserving the high gravimetric energy density of LMR materials
Solution Approach 2:
The patent employs fluorine doping (0.02-0.08) as an intermediary element that mediates between the high-capacity LMR structure and the stability requirement, reducing voltage decay during cycling while maintaining high gravimetric energy density
Data Source
AI summary
A positive electrode active material includes a compound represented by formula 1: Li(1.1+a)Mn(0.51+c)Ni(0.37−x)MxO(2−b)Fb (1), wherein M is Co, Cr, or a combination thereof, 0≤a≤0.02, 0<b<0.01, 0≤c≤0.1, and 0<x<0.1. This positive electrode active material can be used within the context of a lithium-ion battery or a cell of a lithium-ion battery.