Lithium Molybdenum Composite Cathode Material
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Solution Overview
Problem
Lithium secondary batteries face challenges with cobalt's scarcity and environmental toxicity, poor thermal stability of LiNiO2, and low energy density of LiMn2O4 spinel electrodes, necessitating a composite oxide with a layered crystal structure for improved performance.
Innovation Solution
A method for producing a mixed transition metal composite oxide with a high tap density, involving pre-calcination of a transition metal carbonate precursor, blending with lithium and molybdenum sources, and thermal treatment in the range of 600-1000°C, resulting in a cathode material with a spherical morphology and enhanced electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiCoO2 is used as positive electrode material, then stable charge-discharge characteristics and excellent discharge voltage characteristics are achieved, but cobalt is expensive and has environmental toxicity
Solution Approach 1:
The patent uses a composite oxide material Li1+xNiαCoβMnγO2 where multiple metal elements (Ni, Co, Mn) are combined in specific ratios. This composite structure maintains the stable layered crystal structure of LiCoO2 while reducing cobalt content and incorporating cheaper, less toxic elements, thus resolving the contradiction between performance and environmental/cost concerns
Solution Approach 2:
The patent optimizes the local composition by controlling the ratios of different metal elements (Ni: 0.2-0.4, Co: 0.1-0.3, Mn: 0.1-0.3) in specific regions of the composite oxide. This allows different elements to contribute their advantageous properties locally while maintaining overall structural stability and electrochemical performance
2Quantity of substance
If LiNiO2 is used as positive electrode material, then high theoretical capacity is achieved, but poor thermal stability and difficulty in synthesis prevent widespread use
Solution Approach 1:
The patent creates a composite oxide Li1+xNiαCoβMnγO2 that combines Ni (high capacity) with Co (stability) and Mn (thermal stability). The synergistic effect of these elements maintains high theoretical capacity while improving thermal stability, resolving the contradiction between capacity and reliability
Solution Approach 2:
The patent uses a carbonate precursor (NiCO3, CoCO3, MnCO3) as an intermediary substance that facilitates controlled synthesis. The precursor allows for uniform distribution of metal elements before calcination, enabling better control over the final oxide structure and improving both synthesizability and thermal stability
3Ease of manufacture
If LiMn2O4 spinel is used as positive electrode material, then low cost and ease of synthesis are achieved, but theoretical discharge capacity is only about 148 mAh/g resulting in low energy density
Solution Approach 1:
The patent develops a layered composite oxide Li1+xNiαCoβMnγO2 that combines Mn (low cost, easy synthesis) with Ni (high capacity) and Co (structural stability). This composite structure achieves both the ease of manufacturing associated with Mn-based materials and the high energy density associated with Ni-based materials, resolving the contradiction between manufacturability and performance
4Quantity of substance
If conventional cathode materials are used, then standard performance is achieved, but tap density is insufficient resulting in lower specific energy density
Solution Approach 1:
The patent produces cathode materials with spherical particle morphology through controlled calcination of carbonate precursors. The spherical shape improves packing efficiency and increases tap density, which directly enhances specific energy density while maintaining electrochemical performance
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 approach yields cathode materials with higher specific energy densities, excellent cycle life, and low area-specific impedance, suitable for high-performance lithium secondary batteries.
Implementation Method 1
pre-calcination of a transition metal carbonate precursor to obtain an intermediate composite oxide powder
Implementation Method 2
thermally treating the mixture in the temperature range of about 600-1000°C
Data Source
AI summary
A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.