All-Conductive Silicon Electrode Coating for Low-Resistivity Anodes
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Solution Overview
Problem
Conventional battery electrodes face issues with electrode coating layer detachment due to large volume changes of silicon during lithiation and delithiation, leading to electrical isolation and capacity loss, as the silicon's low conductivity and expansion cause solid electrolyte interphase formation and pulverization.
Innovation Solution
The development of all-conductive battery electrodes using a silicon-dominant anode with a conductive pyrolyzed binder and high impurity levels, where the electrode coating layer comprises more than 50% silicon and has a resistivity of less than 100 Ω-cm, ensuring electrical conductivity and stability during charge-discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as the dominant anode material to increase energy density, then the energy density is improved, but the electrode coating layer loses contact with the electrode due to large volume changes during lithiation and delithiation
Solution Approach 1:
The patent changes the electrical conductivity parameter of the binder material by using a conductive binder instead of a conventional non-conductive binder. This parameter change ensures that the binder remains electrically conductive after pyrolysis, maintaining electrical contact between silicon particles and the current collector even when the coating layer detaches physically due to volume changes.
Solution Approach 2:
The patent creates a composite electrode structure where conductive binder material is mixed with silicon particles and coated on the current collector. The conductive binder forms a conductive network that maintains electrical pathways throughout the electrode, compensating for the physical detachment caused by silicon's large volume changes during cycling.
2Ease of manufacture
If conventional non-conductive binder is used in the electrode coating layer, then the manufacturing process is simplified, but electrical isolation occurs leading to capacity loss
Solution Approach 1:
The patent changes the electrical conductivity parameter of the binder material by using a conductive binder instead of a conventional non-conductive binder. This parameter change ensures that the binder remains electrically conductive after pyrolysis, maintaining electrical contact between silicon particles and the current collector even when the coating layer detaches physically due to volume changes.
3Quantity of substance
If high silicon content (>50%) is used in the electrode coating layer to improve energy density, then the energy density is improved, but the resistivity increases causing voltage drops
Solution Approach 1:
The patent creates a composite electrode structure where conductive binder material is mixed with silicon particles and coated on the current collector. The conductive binder forms a conductive network that maintains electrical pathways throughout the electrode, compensating for the physical detachment caused by silicon's large volume changes during cycling.
Solution Approach 2:
The patent changes the electrical conductivity parameter of the binder material by using a conductive binder instead of a conventional non-conductive binder. This parameter change ensures that the binder remains electrically conductive after pyrolysis, maintaining electrical contact between silicon particles and the current collector even when the coating layer detaches physically due to volume changes.
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 maintaining electrical contact and reducing impedance, allowing for stable cycle life and improved energy density, as the conductive binder and silicon work together to prevent voltage drops and electrode separation during expansion and contraction.
Implementation Method 1
the electrode coating layer comprises more than 50% silicon and has a resistivity of less than 100 Ω-cm, ensuring electrical conductivity and stability during charge-discharge cycles
Implementation Method 2
a conductive pyrolyzed binder and high impurity levels, where the electrode coating layer comprises more than 50% silicon
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.