Lithium Anode with Silicon Oxide Layer for Safety
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Solution Overview
Problem
Lithium secondary batteries face safety concerns due to their high energy density, which can lead to explosions or fires, and there is a need for high-capacity anode materials that maintain stability and efficiency during charge and discharge cycles.
Innovation Solution
An anode structure comprising a current collector with a lithium metal layer and a silicon or silicon oxide layer, or a lithium-silicon composite layer, which forms a protective interface that maintains chemical stability and prevents peeling, enhancing safety and cycle efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high-capacity anode material is used to increase battery capacity, then the energy density is improved, but the safety and chemical stability deteriorate due to high energy and risk of explosion or fire
Solution Approach 1:
The patent employs a composite anode structure consisting of multiple layers including a carbonaceous layer, a silicon oxide layer, and a lithium-containing layer. This composite structure combines the high capacity of silicon-based materials with the safety and stability of carbon and lithium compounds, achieving both high energy density and improved safety by distributing the energy storage function across multiple materials with complementary properties.
2Use of energy by moving object
If a high-capacity anode material is used to increase battery capacity, then the energy density is improved, but the chemical stability deteriorates
Solution Approach 1:
The composite anode structure uses silicon oxide and carbonaceous materials that provide chemical stability while lithium-containing layers provide high capacity. The combination maintains compositional stability during charge-discharge cycles while achieving high energy density.
Solution Approach 2:
The patent utilizes thin film structures for the various anode layers, particularly the silicon oxide layer and carbonaceous layer, which act as protective shells that maintain chemical stability while allowing lithium ion transport. These thin films provide a stable interface that prevents degradation of the high-capacity lithium-containing layer.
3Reliability
If a protective layer is applied on lithium metal to improve safety and stability, then the chemical stability is improved, but the protective layer peels off during repeated charging and discharging
Solution Approach 1:
The multi-layer composite structure includes a carbonaceous layer, silicon oxide layer, and lithium-containing layer that work together to maintain adhesion during cycling. The different materials have compatible thermal expansion coefficients and mechanical properties that prevent peeling, while collectively providing chemical stability and high capacity.
Solution Approach 2:
The patent controls the thickness and composition parameters of each layer to optimize performance. The silicon oxide layer thickness and lithium-containing layer composition are specifically designed to maintain structural integrity during volume changes associated with lithium insertion and extraction, preventing delamination while preserving chemical stability.
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 anode structure improves the chemical stability and safety of lithium metal, enhances initial charge and discharge efficiency, and maintains cycle characteristics by preventing the peeling of protective layers during repeated charging and discharging.
Implementation Method 1
a lithium-silicon composite layer provided on the lithium metal layer and containing a lithium-silicon composite in which silicon or silicon oxide is alloyed with lithium
Data Source
AI summary
The present specification relates to an anode, a lithium secondary battery including the same, a battery module including the lithium secondary battery, and a method for manufacturing an anode.