Lithium Mixed Metal Oxide Cathode for Battery Capacity Retention
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Solution Overview
Problem
Conventional lithium mixed metal oxides used in cathode active materials for lithium secondary batteries exhibit insufficient capacity retention in charge and discharge cycle tests, limiting their practical application in non-aqueous electrolyte secondary batteries.
Innovation Solution
A lithium mixed metal oxide with specific composition and structure, characterized by peaks at 1.5 Å and 2.5 Å in the radial distribution function from EXAFS spectra, and a layered crystal structure, is developed, optimizing the ratio of Li, Mn, and M elements to enhance capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium mixed metal oxide (LiNi0.45Mn0.45Co0.1O2) is used as cathode active material, then the battery can be manufactured with existing processes, but the capacity retention in charge and discharge cycle test is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the lithium mixed metal oxide by introducing a specific element M (Fe, Co, Ni, Cu, Zn, or their combinations) and controlling the ratios of Li, Mn, and M elements. This compositional parameter change improves capacity retention while maintaining compatibility with existing manufacturing processes
Solution Approach 2:
The patent creates a composite cathode active material by combining Li, Mn, M elements in specific ratios to form a new lithium mixed metal oxide compound. This composite material approach enhances capacity retention by leveraging the synergistic effects of different metal elements while using conventional synthesis methods
2Reliability
If the composition of lithium mixed metal oxide is optimized with specific elements and ratios, then capacity retention is significantly improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for the composition (Li: 1.4-1.8 mol, Mn: 0.4-1.0 mol, M: varying amounts) that provide optimal capacity retention. These parameter specifications guide manufacturing while accounting for normal process variations, balancing performance requirements with manufacturing feasibility
Solution Approach 2:
The patent introduces element M with specific properties (Fe for stability, Co for conductivity, Ni for capacity) to address specific performance deficiencies in localized aspects of the material functionality, allowing optimization of particular properties without requiring perfect control of all compositional parameters
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 optimized lithium mixed metal oxide significantly improves capacity retention in non-aqueous electrolyte secondary batteries, achieving higher discharge capacities and retention rates compared to conventional materials.
Implementation Method 1
a radial distribution function obtained by subjecting an extended X-ray absorption fine structure (EXAFS) spectrum at K absorption edge of Mn in the oxide to the Fourier transformation
Data Source
AI summary
A lithium mixed metal oxide containing Li, Mn and M (M represents at least one metal element, and is free from Li or Mn), and having a peak around 1.5 Å (peak A), a peak around 2.5 Å (peak B), and the value of IB/IA is not less than 0.15 and not more than 0.9 in a radial distribution function obtained by subjecting an extended X-ray absorption fine structure (EXAFS) spectrum at K absorption edge of Mn in the oxide to the Fourier transformation, wherein IA is the intensity of peak A and IB is the intensity of peak B.