Lithium-Ion Battery Anode Composite for Volume Expansion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium ion secondary batteries face significant capacity deterioration and volume changes during charging and discharging, particularly when using silicon oxide as an anode active material, and there is a lack of understanding regarding the relationship between components, binders, electrolytic solutions, and electrode structures, leading to inadequate performance at higher temperatures.
Innovation Solution
A lithium ion secondary battery design featuring an anode composed of carbon material, metal alloyed with lithium, and metal oxide, bound with a polyimide binder, using a fluorinated chain ether compound electrolyte at 10-75 vol% concentration, and a planar stacking structure to mitigate volume changes and enhance energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon oxide is used as an anode active material, then capacity is improved, but capacity deterioration increases significantly at 45°C or higher
Solution Approach 1:
The anode active material uses a composite structure combining silicon oxide particles with carbon material. The carbon material encapsulates the silicon oxide, forming a composite that maintains the high capacity benefits of silicon oxide while suppressing volume expansion and capacity deterioration through the structural support and flexibility of the carbon matrix.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the anode system by controlling the particle size of silicon oxide (0.1-10 μm), the composition ratio of carbon material (1-50 parts by mass per 100 parts silicon oxide), and the pore volume of the carbon material (0.03-0.5 mL/g). These parameter optimizations enhance lithium ion insertion/extraction efficiency while reducing stress during volume changes, thereby improving reliability at elevated temperatures.
2Use of energy by moving object
If high energy density is pursued, then energy capacity increases, but volume change during charging and discharging increases
Solution Approach 1:
The carbon material acts as a flexible shell surrounding the silicon oxide particles. This flexible carbon matrix can accommodate volume changes during lithium ion insertion and extraction, providing mechanical buffer space that reduces overall volume expansion while maintaining the high energy density benefits of silicon oxide.
Solution Approach 2:
The carbon material is designed with specific pore volume (0.03-0.5 mL/g) and pore structure that provides internal buffer space for volume expansion. The porous structure allows the carbon matrix to absorb and accommodate volume changes of silicon oxide during charging and discharging, reducing net volume change while preserving high energy capacity.
3Ease of operation
If conventional electrolytic solutions are used, then basic battery function is achieved, but carbon dioxide generation increases due to reductive decomposition
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolytic solution by incorporating fluorinated cyclic carbonate (15-40 vol%) and fluorinated chain carbonate (5-30 vol%). These fluorinated compounds have higher electrochemical stability and lower reactivity toward reductive decomposition, thereby reducing carbon dioxide generation while maintaining adequate ionic conductivity and basic battery function.
4Quantity of substance
If silicon-based anode materials are used, then capacity is enhanced, but volume expansion of the anode increases
Solution Approach 1:
The anode active material is constructed as a composite where silicon oxide particles (providing high capacity) are embedded within and encapsulated by carbon material. This composite structure allows the carbon matrix to mechanically constrain and buffer the volume expansion of silicon oxide during lithiation, reducing overall anode volume expansion while preserving the high capacity advantages.
Solution Approach 2:
The carbon material's porous structure with controlled pore volume (0.03-0.5 mL/g) provides internal buffer space that accommodates volume expansion of silicon oxide particles. The pores act as void spaces that absorb expansion stress, allowing the high-capacity silicon oxide to undergo volume changes without transmitting excessive expansion to the overall anode structure.
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 design achieves long-life operation and improved cycle retention ratios, reducing capacity deterioration and volume expansion issues, especially at elevated temperatures, while maintaining high energy density.
Implementation Method 1
carbon material (a) that can absorb and desorb a lithium ion
Implementation Method 2
metal (b) that can be alloyed with lithium
Implementation Method 3
metal oxide (c) that can absorb and desorb a lithium ion
Implementation Method 4
the electrolytic solution comprises a fluorinated chain ether compound
Data Source
Figure 1
AI summary
An exemplary embodiment provides a lithium ion secondary battery using a high energy type anode, which enables long-life operation thereof. A secondary battery according to an exemplary embodiment comprises an electrode element in which a cathode and an anode are oppositely disposed, an electrolytic solution, and an outer packaging body which encloses the electrode element and the electrolytic solution inside; wherein the anode is formed by binding an anode active material, which comprises carbon material (a) that can absorb and desorb a lithium ion, metal (b) that can be alloyed with lithium, and metal oxide (c) that can absorb and desorb a lithium ion, to an anode collector with an anode binder; and wherein the electrolytic solution comprises a liquid medium which is hard to generate carbon dioxide at a concentration of 10 to 75 vol%.