Silicon Composite Anodes With Polymer Electrolyte Buffering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Silicon-based anodes in all-solid-state lithium-ion batteries face challenges due to volume changes during lithiation and delithiation, leading to mechanical degradation, electric contact loss, and poor cycling performance, resulting in capacity losses and short cycle life.
Innovation Solution
Development of ceramic-polymer composite anodes with a high-ionic-conductivity electrolyte that forms a robust polymer networking structure, incorporating silicon-based active materials, ceramic nanoparticles, and a polymer coating to stabilize the anode and maintain intimate contact with the solid-state electrolyte, enhancing lithium-ion transport and mechanical resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon-based anodes are used to increase lithium storage capacity, then energy density is improved, but mechanical degradation and poor cycling performance occur due to volume changes
Solution Approach 1:
The silicon anode is divided into nanoparticles dispersed within a polymer matrix, preventing particle isolation and maintaining structural integrity during volume changes. This segmentation allows the silicon to expand and contract without causing macroscopic mechanical degradation.
Solution Approach 2:
The polymer matrix and electrolyte network are pre-configured to accommodate silicon volume changes before they occur. The resilient polymer structure is designed in advance to buffer expansion up to 300% and maintain electrode integrity throughout cycling.
Solution Approach 3:
A composite anode structure is created combining silicon nanoparticles, polymer matrix, conducting agent, and electrolyte-infiltrated network. This composite approach leverages the high capacity of silicon while the polymer and electrolyte provide mechanical stability and ionic conductivity.
2Quantity of substance
If silicon anode volume expands during delithiation, then lithium storage capacity increases, but mechanical degradation and electric contact loss occur
Solution Approach 1:
The resilient polymer matrix and electrolyte network are designed to cushion and accommodate silicon expansion before it causes mechanical damage. The polymer's elasticity allows it to stretch and compress, absorbing the mechanical stress of volume changes and preventing particle isolation and electrode cracking.
3Ease of operation
If SEI layers continuously form and break down on silicon particles, then lithium-ion transport occurs, but capacity losses and electrolyte consumption increase
Solution Approach 1:
The electrolyte-infiltrated polymer network acts as an intermediary between the silicon particles and the external environment. It provides stable ionic transport pathways while protecting the silicon surface, reducing unnecessary SEI formation and breakdown, and maintaining intimate contact throughout cycling.
4Reliability
If graphite anodes are used to ensure stability and good cycle-life, then durability is improved, but energy density decreases due to low lithium storage capacity
Solution Approach 1:
The invention creates a composite anode that combines silicon nanoparticles with a resilient polymer matrix and electrolyte network. This composite structure enables the system to achieve the high capacity of silicon (4200 mAh/g) while the polymer matrix provides the stability and structural integrity traditionally associated with graphite anodes.
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 results in improved energy density, extended cycle life, and high charge/discharge rates, with a reduced anode thickness and weight, while maintaining stable performance over repeated cycles.
Implementation Method 1
The infiltrated electrolyte has high ionic conductivity and a robust polymer networking structure. The Si-based anode could be fabricated using established industry lines and the resultant anode sheet can be directly incorporated into the manufacturing of ASSLiBs that exhibit high energy density, long cycle life, and high charge/discharge rates.
Implementation Method 2
However, typical silicon anodes have a low cycle life due to the stresses associated with the large changes in volume of 300% as the lithium ions are transported into and out of the silicon anode during the lithiation and delithiation process over repeated charging and discharging cycles.
Implementation Method 3
Development of ceramic-polymer composite anodes with a high-ionic-conductivity electrolyte that forms a robust polymer networking structure, incorporating silicon-based active materials, ceramic nanoparticles, and a polymer coating to stabilize the anode
Implementation Method 4
The present invention is based in part on the development of electrolyte-infiltrated silicon-based composite anodes that are particularly suited for all solid-state lithium-ion batteries (ASSLiBs). The infiltrated electrolyte has high ionic conductivity and a robust polymer networking structure.
Data Source
AI summary
High energy density and long cycle life all solid-state electrolyte lithium-ion batteries use ceramic-polymer composite anodes which include a polymer matrix with ceramic nanoparticles, silicon-based anode active materials, conducting agents, lithium salts and plasticizer distributed in the matrix. The silicon-based anode active material are anode active particles formed by high energy milling a mixture of silicon, graphite, and metallic and/or non-metallic oxides. A polymer coating is applied to the particles. The networking structure of the electrolyte establishes an effective lithium-ion transport pathway in the electrode and strengthens the contact between the electrode layer and solid-state electrolyte resulting in higher lithium-ion battery cell cycling stability and long battery life.