Nickel Layered Cathode Composition for Low Oxygen Desorption
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Solution Overview
Problem
Existing lithium transition metal complex oxides used in non-aqueous electrolyte secondary batteries face challenges in safety, particularly at high voltages, due to gas generation during charging, and require improved capacitance and cycle characteristics.
Innovation Solution
A positive electrode active material comprising a layer-structured nickel-containing lithium transition metal complex oxide with specific ratios of titanium and niobium in the chemical composition, which stabilizes the crystal structure and reduces oxygen gas desorption, enhancing safety and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium transition metal complex oxides are used as positive electrode active material, then high voltage (4V) and large capacitance are achieved, but safety deteriorates due to gas generation during charging
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core contains nickel-rich lithium transition metal complex oxide for high capacitance, while the outer shell contains aluminum and manganese with specific ratios to suppress oxygen evolution and improve safety. This spatial differentiation allows different regions to perform different functions: the core provides high power density while the shell provides structural stability and safety.
Solution Approach 2:
The patent uses composite materials by combining nickel-containing lithium transition metal complex oxide with aluminum and manganese compounds to form a multi-element composite structure. The specific composition ratios (Ni: 0.3-0.8, Al: 0.05-0.2, Mn: 0.05-0.2) create a composite material that leverages the high capacitance of nickel while the aluminum and manganese components suppress gas generation and improve thermal stability.
2Quantity of substance
If nickel content is increased to improve capacitance, then charge and discharge capacity increases, but oxygen gas desorption increases reducing safety
Solution Approach 1:
The patent converts the harmful effect of oxygen evolution into a beneficial outcome by using aluminum and manganese as sacrificial elements that preferentially oxidize, thereby protecting the nickel from excessive oxygen release. The aluminum and manganese components act as oxygen buffers that undergo controlled oxidation reactions, converting the potentially harmful oxygen evolution into a controlled electrochemical process that maintains safety while preserving high capacitance.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the compositional parameters of the positive electrode active material. The nickel content is optimized to 0.3-0.8 to maintain high capacitance, while aluminum (0.05-0.2) and manganese (0.05-0.2) are added in specific amounts to suppress oxygen desorption. The voltage range is also controlled (3.0-4.3V) to operate within a safe window that balances capacitance and safety.
3Use of energy by moving object
If high voltage charging is performed to increase power output, then energy density improves, but crystal structure instability increases leading to reduced cycle life
Solution Approach 1:
The patent applies beforehand cushioning by incorporating aluminum and manganese elements in advance into the crystal structure to prevent structural degradation during high-voltage charging. These elements act as structural buffers that maintain lattice stability under high voltage stress, cushioning against the destabilizing effects of high energy density operation and thereby extending cycle life.
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 material significantly reduces oxygen gas desorption, improving safety and maintaining high electric charge and discharge capacitance, especially at high voltages, thereby enhancing the stability and performance of non-aqueous electrolyte secondary batteries.
Implementation Method 1
The lithium transition metal complex oxide contains titanium and niobium in the chemical composition, and the ratio of the total number of moles of titanium and niobium relative to the total number of moles of metals excluding lithium is 0.04 or less
Implementation Method 2
The material significantly reduces oxygen gas desorption, improving safety and maintaining high electric charge and discharge capacitance
Implementation Method 3
A positive electrode active material for a non-aqueous electrolyte secondary battery
Implementation Method 4
The method includes preparing a raw material mixture containing a nickel-containing compound, a lithium-containing compound, a titanium-containing compound, and a niobium-containing compound, and heat-treating the raw material mixture
Data Source
AI summary
A positive electrode active material for a non-aqueous electrolyte secondary battery is provided. The positive electrode active material includes a layer-structured, nickel-containing lithium transition metal complex oxide. The lithium transition metal complex oxide contains titanium and niobium in a chemical composition thereof, and has a ratio of a total number of moles of titanium and niobium relative to a total number of moles of metals excluding lithium in the chemical composition of 0.04 or less.