Silicon Core Anode with Metal Oxide Carbon Shell
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Solution Overview
Problem
Lithium batteries with silicon-based anode active materials face deterioration due to volume changes during charging and discharging, leading to poor cycle characteristics and increased internal resistance.
Innovation Solution
A composite anode active material is developed, comprising a silicon-containing core coated with a shell of metal oxide and carbonaceous material, which reduces volume change and side reactions, enhancing the battery's cyclic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon-based anode active materials are used to achieve high capacity, then the energy density is improved, but the volume change during charging and discharging causes deterioration and poor cycle characteristics
Solution Approach 1:
The patent applies the nesting principle by placing the silicon-containing core inside a protective shell structure. The core (silicon-based material) is nested within the shell (metal oxide and carbonaceous material layers), allowing the high-capacity silicon to expand and contract during charging/discharging while being contained and protected by the surrounding shell structure, thus preventing deterioration and maintaining cycle characteristics.
Solution Approach 2:
The patent applies composite materials by creating a composite structure consisting of a silicon-containing core combined with a shell made of metal oxide and carbonaceous material. This composite anode active material combines the high capacity of silicon with the structural stability and protective properties of the shell materials, resolving the contradiction between high energy density and reliable cycle characteristics.
2Use of energy by moving object
If silicon-based anode active materials are used to achieve high capacity, then the energy density is improved, but the internal resistance increases due to side reactions
Solution Approach 1:
The patent applies the intermediary principle by introducing a shell structure composed of metal oxide and carbonaceous material as an intermediary layer between the silicon-containing core and the electrolyte. This shell acts as a mediator that prevents direct contact between the silicon core and electrolyte, thereby reducing side reactions and the formation of unstable SEI films, which in turn reduces internal resistance while maintaining high energy density.
3Reliability
If a protective shell is added to prevent volume change, then the cycle characteristics are improved, but the device complexity increases
Solution Approach 1:
The patent applies flexible shells and thin films by using a shell structure made of metal oxide and carbonaceous material that can flexibly accommodate the volume changes of the silicon core during charging and discharging. The shell is designed with appropriate thickness and compositional flexibility to provide protection without creating a rigid, complex structure, thus improving cycle characteristics while minimizing device complexity.
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 composite anode active material effectively suppresses volume change and internal resistance, improving the cycle characteristics and durability of lithium batteries.
Implementation Method 1
the shell may include at least one first metal oxide represented by Formula MaOb (0 < b/a ≤ 2/3), and a first carbonaceous material, wherein: the first metal oxide is placed in the first carbonaceous material... the shell on and conformed to a surface of the core... prevents deterioration due to volume change
Implementation Method 2
the shell on and conformed to a surface of the core... prevents deterioration... suppresses side reactions... improving the cycle characteristics and durability
Data Source
AI summary
A composite anode active material, an anode including the composite anode active material, and a lithium battery including the anode are provided. The composite anode active material includes a core and a shell on and conformed to the surface of the core. The core includes a silicon-containing structure, a silicon-containing compound, or a combination thereof, and the shell includes at least one first metal oxide represented by MaOb (0<a≤3, 0<b<4, and when a is 1, 2, or 3, b is not an integer) and a first carbonaceous material, where the first metal oxide is located inside a matrix of first carbonaceous material, and M includes at least one metal selected from among Group 2 to Group 13, Group 15, and Group 16 of the Periodic Table of Elements.