Nickel-Rich Composite Cathode Suppresses Oxygen Release
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Solution Overview
Problem
Current lithium-ion battery cathode materials, such as LiCoO2, suffer from high costs, biological toxicity, and reduced efficiency due to cobalt deposits, and nickel-containing mixed oxide materials exhibit sub-optimal cycle life despite high capacities, necessitating the development of new materials and methods for high-capacity, long-cycle-life lithium-ion batteries.
Innovation Solution
A composite material is created by mixing a high nickel content lithium storage material with a transition metal oxide lithium storage material and a lithium source, followed by sintering, using ball milling to enhance capacity and cycle life, resulting in a lithiated composite material with improved performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-containing mixed oxide materials are used as cathode materials, then high capacity is achieved, but cycle life becomes sub-optimal due to high oxidation power and oxygen release
Solution Approach 1:
The patent applies composite materials by combining nickel-containing mixed oxide particles with transition metal oxide or sulfide particles to create a composite cathode material. This composite structure allows the high capacity of nickel-based materials to be maintained while the transition metal component suppresses oxygen release and improves cycle life, directly resolving the contradiction between capacity and reliability
2Reliability
If LiCoO2 is used as cathode material, then stable charge-discharge characteristics and high electronic conductivity are achieved, but cost increases, biological toxicity occurs, and efficiency decreases due to cobalt deposits
Solution Approach 1:
The patent extracts cobalt from the cathode material composition by using nickel-containing mixed oxides as the primary active material and transition metal oxides or sulfides as additives. This extraction eliminates cobalt-related toxicity and cost issues while maintaining stable charge-discharge characteristics through the synergistic composite structure
Solution Approach 2:
The patent changes the chemical composition parameters by using nickel-rich mixed oxides (such as Ni0.8Co0.1Mn0.1O2) combined with transition metal oxides or sulfides in specific ratios. This parameter change achieves stable electrochemical performance without cobalt, resolving the contradiction between reliability and harmful factors
3Reliability
If materials are combined to resist capacity losses, then cycle life improves, but specific capacity decreases significantly
Solution Approach 1:
The patent optimizes the composition parameters by using nickel-containing mixed oxide as the dominant phase (80-95 wt%) with transition metal oxide or sulfide as a minor component (5-20 wt%). This parameter optimization maintains high specific capacity while achieving improved cycle life, resolving the contradiction between reliability and quantity of substance
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 composite material maintains a capacity of over 180 mAh/g at 40 cycles and demonstrates significantly improved cycle life compared to high nickel content materials alone, with capacities exceeding 170 mAh/g at 20 cycles, addressing the limitations of existing materials.
Implementation Method 1
During the charging of the battery, lithium ions travel from the cathode to the anode and are intercalated therein. During discharge of the battery, the process reverses.
Implementation Method 2
nickel-containing mixed oxide materials... suffer from sub-optimal cycle life as a result of their high oxidation power and oxygen release
Data Source
AI summary
Lithiated composite materials and methods of manufacture are provided that are capable of imparting excellent capacity and greatly improved cycle life in lithium-ion secondary cells. By supplementing a high nickel content lithium storage material with a transition metal oxide lithium storage material or a dopant at relatively low levels, the capacity of the high nickel content lithium storage materials is maintained while cycle life is dramatically improved. These characteristics are promoted by methods of producing the materials that intermix unlithiated precursor materials with a lithium source and sintering the materials together in a single sintering reaction. The resulting lithiated composite materials provide for the first time both high capacity and excellent cycle life to predominantly high nickel content electrodes.