Silicon Oxide Anode with Lithium-Unreactive Metal Coating
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Solution Overview
Problem
Lithium batteries using metal alloy anodes suffer from volume expansion issues during charging/discharging, leading to capacity retention problems and electrolyte decomposition, while metal oxides have poor life characteristics.
Innovation Solution
An anode active material comprising a silicon oxide core coated with a metal layer unreactive to lithium, such as nickel, copper, or titanium, which improves conductivity and suppresses volume changes, thereby enhancing discharge capacity and life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal alloy anodes are used to increase discharge capacity, then the battery capacity is improved, but volume expansion occurs during charging/discharging leading to capacity retention problems and electrolyte decomposition
Solution Approach 1:
The patent applies the nesting principle by placing the silicon oxide core (which provides high discharge capacity) inside a protective coating layer of lithium-unreactive metal. This nested structure allows the inner core to expand and contract during charging/discharging cycles without causing damage to the electrode structure or triggering electrolyte decomposition, thus maintaining both high capacity and good capacity retention.
Solution Approach 2:
The patent uses composite materials by combining silicon oxide (for high capacity) with a coating layer of lithium-unreactive metal (for structural stability). This composite structure resolves the contradiction by allowing the silicon oxide core to provide high discharge capacity while the coating layer prevents volume expansion issues, maintaining capacity retention and preventing electrolyte decomposition over multiple cycles.
2Ease of manufacture
If metal oxide anodes are used to reduce cost, then manufacturing cost is reduced, but life characteristics are poor
Solution Approach 1:
The patent applies composite materials by combining silicon oxide (which has better life characteristics than traditional metal oxides) with a coating layer of lithium-unreactive metal. This composite structure improves life characteristics compared to uncoated metal oxides while maintaining cost-effectiveness, as the coating layer is thin and uses common metals like nickel, copper, or aluminum.
Solution Approach 2:
The patent changes the chemical composition parameters by selecting specific metals (nickel, copper, aluminum) for the coating layer that have low reactivity with lithium. This parameter change (choosing lithium-unreactive metals) improves life characteristics by preventing unwanted chemical reactions during cycling, while keeping the manufacturing process simple and cost-effective.
3Stability of the object's composition
If silicon oxide is used as anode material to suppress volume expansion, then structural stability is improved, but conductivity is poor leading to reduced discharge capacity
Solution Approach 1:
The patent uses composite materials by combining silicon oxide (which provides structural stability and volume expansion suppression) with a coating layer of conductive lithium-unreactive metal. This composite structure resolves the conductivity issue by providing a conductive pathway through the coating layer, enabling electrons to reach the silicon oxide core effectively, thus maintaining both structural stability and high discharge capacity.
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 silicon oxide anode active material with a lithium-unreactive metal coating improves the lithium battery's discharge capacity and life characteristics by maintaining conductivity and preventing cracking, while being cost-effective for mass production.
Implementation Method 1
a coating layer which includes metal unreactive toward lithium... formed on the core at least partially
Implementation Method 2
improves conductivity and suppresses volume changes
Data Source
AI summary
An anode active material. The anode active material includes a core including SiOx (0.5≦x≦1.7), and a coating layer formed on the core at least partially. The coating layer includes metal unreactive toward lithium.