Porous Silicon Anode Active Material for Lithium Battery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current anode active materials in lithium secondary batteries face challenges such as volumetric swelling or shrinkage during charging and discharging, leading to decreased capacity retention, efficiency, and lifespan, limiting their performance as high-capacity negative active materials.
Innovation Solution
A porous silicon anode active material with uniform pore diameters ranging from 50 nm to 80 nm is developed by heat-treating a silicon aluminum alloy in an inert gas atmosphere and selectively removing aluminum using an acidic solution, which controls porosity and pore size to suppress volume expansion and enhance energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-carbonaceous materials such as silicon are used as anode active material to increase capacity, then the capacity of the battery is improved, but volumetric swelling during charging and discharging leads to decreased capacity retention ratios and lifespan characteristics
Solution Approach 1:
The patent applies porous silicon as the anode active material, where the porous structure provides void spaces that can accommodate volume expansion during lithium insertion. The pores act as buffers that absorb the mechanical stress of swelling, preventing structural degradation and maintaining capacity retention over multiple cycles while preserving high capacity.
Solution Approach 2:
The patent uses composite materials by combining silicon with other materials in a porous structure. This composite approach allows the silicon to provide high capacity while the porous framework and surrounding materials constrain volume expansion and reduce stress-related destructive phenomena, thereby improving both capacity and reliability.
2Reliability
If porous silicon with controlled pore diameter is used to suppress volume expansion, then capacity retention and lifespan are improved, but the complexity of manufacturing increases
Solution Approach 1:
The patent controls the pore diameter as a specific parameter within the range of 50-80 nm to optimize the balance between volume expansion suppression and manufacturing feasibility. By defining a specific parameter range rather than requiring precise control at a single value, the manufacturing complexity is reduced while still achieving the desired performance improvement in capacity retention and lifespan.
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 porous silicon anode active material effectively improves the cycle characteristics and life characteristics of lithium secondary batteries by maintaining a high discharge capacity and reducing stress-related destructive phenomena, resulting in enhanced performance.
Implementation Method 1
Lithium secondary batteries produce electrical energy by oxidation and reduction reactions that occur when lithium ions are intercalated to or deintercalated from a cathode and an anode
Implementation Method 2
selectively removing the aluminum by performing etching on a resultant of the heat-treating with an acidic solution
Data Source
AI summary
An anode active material including a porous silicon having pores with a uniform average pore diameter, wherein the average pore diameter of the pores is in a range of about 50 nm to about 80 nm, a method of preparing the anode active material, and a lithium secondary battery including an anode including the anode active material.