Porous Silicon Oxide Anode for Lithium Battery Volume Expansion
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Solution Overview
Problem
Lithium secondary batteries face rapid capacity decrease and shortened cycle lifetime due to volume changes and cracking/pulverization of metal (metalloid) based electrode active materials like silicon and tin during charge and discharge.
Innovation Solution
A porous electrode active material using silicon-based oxide (SiOx with 0.5≦x≦1.2) with a controlled Brunauer, Emmett, and Teller (BET) specific surface area of 2 m2/g to 100 m2/g and porosity of 5% to 90%, which is coated with carbon to reduce volume expansion and enhance mechanical strength, and a method involving electrochemical deposition and etching to form a honeycomb structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal (metalloid) based electrode active material like silicon or tin is used to increase capacity, then charge and discharge capacity is improved, but volume changes cause cracks and pulverization leading to rapid capacity decrease and shortened cycle lifetime
Solution Approach 1:
The patent applies porous silicon-based oxide material with controlled pore structure (porosity of 30-80% and specific surface area of 10-100 m²/g) to accommodate volume expansion during lithium insertion/extraction. The porous structure prevents cracks and pulverization by providing internal space for volume changes, thereby maintaining cycle lifetime while preserving high capacity
Solution Approach 2:
The patent uses composite silicon-based oxide material combining silicon oxide (SiOx where 0.8 ≤ x ≤ 1.5) with porous structure and carbon coating. This composite approach integrates the high capacity of silicon with the structural stability of porous morphology and carbon protective layer, resolving the contradiction between capacity and cycle lifetime
2Quantity of substance
If metal (metalloid) based electrode active material is used to achieve high capacity, then electrode capacity is improved, but mechanical strength decreases due to cracks and pulverization
Solution Approach 1:
The porous structure with controlled porosity (30-80%) and specific surface area (10-100 m²/g) provides mechanical integrity while accommodating volume expansion. The porous framework distributes stress uniformly, preventing crack propagation and maintaining mechanical strength throughout charge and discharge cycles
Solution Approach 2:
The carbon-coated porous silicon-based oxide composite enhances mechanical strength by forming a flexible protective layer that constrains the silicon oxide framework. This composite structure prevents pulverization while maintaining electrical conductivity and capacity
3Reliability
If conventional electrode active material like carbon is used to ensure stability and low cost, then reversibility and price are improved, but capacity is lower than metal based materials
Solution Approach 1:
The patent changes the chemical composition parameter by using silicon-based oxide (SiOx where 0.8 ≤ x ≤ 1.5) instead of conventional carbon materials. This compositional change enables high capacity (exceeding carbon materials) while the porous structure and carbon coating maintain reversibility through controlled volume expansion and protective effects
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 solution effectively prevents cracking and pulverization, improving the battery's capacity and lifetime by controlling volume changes and maintaining mechanical strength, while allowing for efficient charge and discharge processes.
Implementation Method 1
a porous electrode active material including silicon-based oxide expressed by SiOx (0.5≦x≦1.2) and having a Brunauer, Emmett, and Teller (BET) specific surface area ranging from 2 m2/g to 100 m2/g
Implementation Method 2
a method involving electrochemical deposition and etching to form a honeycomb structure
Data Source
AI summary
Provided are an electrode active material having a plurality of pores and a secondary battery including the same, and more particularly, a porous electrode active material including silicon-based oxide expressed by SiOx (0.5≦x≦1.2) and having a Brunauer, Emmett, and Teller (BET) specific surface area ranging from 2 m2/g to 100 m2/g, and a secondary battery including a cathode including a cathode active material, a separator, an anode including an anode active material, and an electrolyte, in which the anode active material includes a porous electrode active material including silicon-based oxide expressed by SiOx (0.5≦x≦1.2) and having a BET specific surface area ranging from 2 m2/g to 100 m2/g.