Silicon Anode with Carbon-Hydrogen Coating for Cycle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Silicon-based anode active materials in secondary batteries are prone to cracking during charge and discharge cycles, leading to increased surface reactivity and reduced battery performance due to the expansion and contraction of silicon, which results in electrolyte decomposition and decreased battery characteristics.
Innovation Solution
A silicon-based anode active material with a carbon and hydrogen-containing covering section, where specific positive ions detected by time-of-flight secondary ion mass spectrometry (TOF-SIMS) are used to reduce surface reactivity and enhance the battery's cycle characteristics and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as anode active material to increase battery capacity, then the battery capacity is greatly improved, but the anode active material is easily cracked due to expansion and shrinkage
Solution Approach 1:
A carbon-based coating layer is applied on the surface of silicon particles to form a flexible protective shell. This shell accommodates the expansion and shrinkage of silicon during charge-discharge cycles, preventing cracking while maintaining structural integrity. The coating acts as a buffer that absorbs mechanical stress.
Solution Approach 2:
The anode is designed as a composite structure combining silicon core particles with a carbon-based outer layer. This composite material approach leverages the high capacity of silicon while utilizing the mechanical strength and flexibility of carbon to prevent degradation during cycling.
2Quantity of substance
If the surface area of anode active material is increased to improve battery capacity, then the battery capacity is improved, but the decomposition reaction of electrolytic solution occurs more easily
Solution Approach 1:
A carbon-based coating layer serves as an intermediary between the silicon surface and the electrolyte. This intermediate layer reduces direct contact between the reactive silicon surface and the electrolyte, suppressing decomposition reactions while still allowing lithium ion transport.
Solution Approach 2:
The carbon-based coating creates an inert environment around the silicon particles, protecting the highly reactive silicon surface from direct interaction with the electrolyte. This inert barrier prevents unwanted side reactions while maintaining electrochemical functionality.
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 proposed solution improves the battery's cycle stability and energy density by reducing surface reactivity and electrolyte decomposition, leading to superior battery performance and extended lifespan.
Implementation Method 1
the covering section includes carbon (C) and hydrogen (H) as constituent elements... one or more of positive ions represented by CxHy... are detected by positive ion analysis of the covering section
Implementation Method 2
one or more of positive ions represented by CxHy (x and y satisfy 2≦x≦6 and 3≦y≦9) are detected by positive ion analysis of the covering section with the use of time-of-flight secondary ion mass spectrometry
Data Source
AI summary
A secondary battery includes: a cathode; an anode including an active material; and an electrolytic solution, wherein the active material includes a central section and a covering section provided on a surface of the central section, the central section includes silicon (Si) as a constituent element, the covering section includes carbon (C) and hydrogen (H) as constituent elements, and one or more of positive ions represented by CxHy (x and y satisfy 2≦x≦6 and 3≦y≦9) are detected by positive ion analysis of the covering section with the use of time-of-flight secondary ion mass spectrometry.