All-Conductive Silicon Electrode Coating for Contact Stability
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Solution Overview
Problem
Conventional battery electrodes face issues where the electrode coating layer can lose contact with the electrode due to expansion and contraction during lithiation and delithiation, leading to capacity loss and reduced cycle life.
Innovation Solution
The development of all-conductive battery electrodes, where the electrode coating layer comprises more than 50% silicon and features a pyrolyzed carbon binder, ensuring electrical conductivity and maintaining contact throughout volume changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional battery electrodes are used, then the electrode structure is simple and easy to manufacture, but the electrode coating layer loses contact with the electrode during expansion and contraction, leading to capacity loss
Solution Approach 1:
The electrode coating layer is divided into multiple segments or sections that can independently expand and contract during lithiation and delithiation processes. This segmentation allows each section to maintain contact with the current collector while accommodating volume changes, preventing complete detachment of the coating layer.
Solution Approach 2:
A flexible buffer layer or thin film structure is introduced between the electrode coating layer and the current collector. This flexible layer accommodates the expansion and contraction of the silicon-based coating during cycling, maintaining electrical contact while allowing volume changes without causing detachment.
2Duration of action of stationary object
If electrode coating layer maintains contact during volume changes, then capacity retention is improved, but the electrode structure becomes more complex
Solution Approach 1:
The electrode structure is pre-designed with expansion spaces, buffer zones, or compliant layers before the lithiation process begins. These preliminary structural features are built into the electrode to anticipate and accommodate the volume expansion that occurs during silicon lithiation, preventing contact loss before it happens.
Solution Approach 2:
The physical parameters of the electrode structure are modified, such as changing the thickness ratios of different layers, adjusting the porosity of the coating layer, or modifying the mechanical properties of the binder material. These parameter changes allow the electrode to maintain contact stability while accommodating volume changes during cycling.
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
This solution enhances cell capacity retention by minimizing capacity loss from separated electrode coating layers, maintaining efficient electrical contact, and improving the cycle life of silicon-dominant anodes.
Implementation Method 1
the electrode coating layer comprises more than 50% silicon and features a pyrolyzed carbon binder
Data Source
AI summary
Systems and methods for all-conductive battery electrodes may include an electrode coating layer on a current collector, where the electrode coating layer comprises more than 50% silicon, and where each material in the electrode has a resistivity of less than 100 Ω-cm. The silicon may have a resistivity of less than 10 Ω-cm, less than 1 Ω-cm, or less than 1 mΩ-cm. The electrode coating layer may comprise pyrolyzed carbon and/or conductive additives. The current collector comprises a metal foil. The metal current collector may comprise one or more of a copper, tungsten, stainless steel, and nickel foil in electrical contact with the electrode coating layer. The electrode coating layer comprises more than 70% silicon. The electrode may be in electrical and physical contact with an electrolyte. The electrolyte may comprise a liquid, solid, or gel. The battery electrode may be in a lithium ion battery.