Silicon Core-Shell Anode Material for Volume-Change Stability
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Solution Overview
Problem
Silicon anode materials in lithium batteries experience structural instability due to extreme volume changes during charge-discharge cycles, leading to reduced battery life and safety concerns.
Innovation Solution
A core-shell structure is developed, where a silicon core is surrounded by a polymer shell with a siloxane group and carboxyl or ester group, providing elasticity and preventing direct contact with the electrolyte to maintain structural integrity and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon material is used as anode to achieve high energy density, then the battery's energy density is improved, but the anode volume changes extremely and cracks during charge-discharge cycles
Solution Approach 1:
The patent applies a core-shell structure where a silicon core is nested within a polymer shell. The silicon core provides high energy density while the surrounding polymer shell accommodates volume changes and prevents cracking, effectively nesting the problematic high-performance material within a protective structure.
Solution Approach 2:
The patent uses a polymer shell with siloxane groups that provides flexibility to accommodate the extreme volume changes of silicon during lithiation and delithiation. This flexible shell prevents the silicon core from cracking while maintaining structural integrity throughout charge-discharge cycles.
2Stability of the object's composition
If polymer shell with siloxane group is added to maintain structural integrity, then the anode structural stability is improved, but the device complexity increases
Solution Approach 1:
The patent creates a composite material system combining silicon core with a polymer shell containing siloxane groups. This composite structure integrates the high energy density of silicon with the structural stability and flexibility of the polymer, achieving both performance and stability goals through material composition rather than complex mechanical designs.
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 core-shell structure enhances the battery's energy density, capacity, and cycle life while ensuring safety by accommodating volume changes and preventing impedance increases.
Implementation Method 1
the polymer includes a first structure and a second structure, the first structure includes a siloxane group
Implementation Method 2
the polymer is linear, the polymer includes a first structure and a second structure... adapted to the extremely volume change of the silicon material
Implementation Method 3
the second structure includes a carboxyl group or an ester group... maintaining structural integrity and ionic conductivity
Data Source
AI summary
A battery material is a core-shell structure, and the core-shell structure includes a core and a shell. The shell surrounds the core. A composition of the core is a silicon material. The shell includes a polymer, the polymer is linear, the polymer includes a first structure and a second structure, the first structure includes a siloxane group, and the second structure includes a carboxyl group or an ester group. The first structure is more adjacent to the core than the second structure.