Covalently Bonded Battery Electrodes for Extreme Fast Charging
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Solution Overview
Problem
Existing electrodes in lithium-ion batteries face challenges with high electronic and ionic impedance, leading to slow charging times and reduced energy density, especially when attempting to achieve extreme fast charging (XFC) standards.
Innovation Solution
The development of novel electrodes with covalently bonded active materials and current collectors using electrically conductive, covalently bonded interfaces, which enhances electronic conductivity and bonding strength, thereby reducing impedance and improving charging rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrode thickness is increased to improve energy density, then energy density is improved, but resistance to electron flow increases significantly
Solution Approach 1:
The patent employs composite materials consisting of carbonaceous particles (graphite, activated carbon, carbon black, graphene, or carbon nanotubes) combined with metalloid particles (silicon, germanium, tin, or their alloys). This composite structure provides both the high capacity needed for energy density and the conductive pathways necessary for electron transport, resolving the contradiction between thickness/energy density and electronic conductivity.
2Strength
If polymeric binders are used to hold particulate structure together, then structural integrity is improved, but resistance to electron flow increases
Solution Approach 1:
The patent eliminates polymeric binders from the electrode composition entirely. Instead, it relies on the inherent mechanical interlocking and conductive contact between carbonaceous and metalloid particles, as well as between particles and the current collector. This extraction of the harmful binder component resolves the contradiction by providing structural integrity through particle packing while maintaining continuous electron pathways.
3Quantity of substance
If conventional casting methods are used to create thicker functional electrode films, then energy density is improved, but contact area between particles decreases
Solution Approach 1:
The patent changes the fundamental parameters of electrode fabrication by abandoning conventional slurry casting in favor of a dry powder compression method. This parameter change allows for superior particle packing density and maximized contact area between particles and current collector, enabling thick electrodes (>100 μm) to maintain high electronic conductivity while achieving high active material loading for improved energy density.
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 approach allows for the achievement of extreme fast charging capabilities while maintaining energy density, as evidenced by improved capacity retention and cycling performance at high current densities.
Implementation Method 1
heating the mixture to a temperature sufficient to form covalent bonds between the carbonaceous material and the metalloid material
Data Source
AI summary
An electrode comprising covalently bonded interfaces between electrode active particles and between electro active particles and current collectors. In one aspect, the bonds comprise carbides or alloys. A method of forming such electrodes is also provided. Batteries and the like comprising the electrodes are also provided.