Solid-State Battery Electrodes With Graphene-Wrapped Silicon Anodes
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Solution Overview
Problem
Conventional lithium-ion secondary batteries face issues such as electrolyte leakage, decomposition, and the risk of ignition due to liquid use, while solid-state batteries using silicon as a negative electrode material experience expansion and contraction problems, leading to potential short circuits and safety concerns.
Innovation Solution
The use of graphene compounds to bind and fix negative electrode active material particles, surround solid electrolyte interfaces, and enhance conductivity, preventing expansion and contraction, and reducing the risk of micro short circuits by forming a conductive path and stabilizing the electrode materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid electrolyte is used in secondary battery, then high capacity can be achieved, but safety problems occur including leakage, decomposition, and ignition risk
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, eliminating the safety issues associated with liquid electrolytes (leakage, decomposition, ignition) while maintaining high battery capacity through the solid electrolyte's ionic conductivity
Solution Approach 2:
The patent uses composite materials including graphene compounds combined with solid electrolytes to create a structure that provides both high ionic conductivity for capacity and enhanced safety by eliminating liquid components
2Quantity of substance
If silicon is used as negative electrode active material, then high capacity is achieved, but expansion and contraction occur during charging and discharging
Solution Approach 1:
The patent employs graphene compound thin films to wrap around silicon negative electrode particles, providing a flexible protective shell that accommodates expansion and contraction during charging-discharging cycles while maintaining structural integrity
Solution Approach 2:
The patent creates composite structures where silicon particles are combined with graphene compounds and solid electrolytes, forming a composite material system that maintains high capacity while suppressing volume changes through the reinforcing graphene network
3Reliability
If solid electrolyte is used to eliminate liquid leakage, then safety is improved, but interface resistance between solid electrolyte and electrodes increases
Solution Approach 1:
The patent uses composite materials combining graphene compounds with solid electrolytes at the interface, creating a composite layer that maintains the safety benefits of solid electrolytes while reducing interface resistance through the highly conductive graphene component
Solution Approach 2:
The patent introduces graphene compound layers as intermediary materials between the solid electrolyte and electrode active materials, facilitating better interfacial contact and ionic transport while maintaining the overall safety of the solid-state system
4Stability of the object's composition
If graphene compound is used to fix negative electrode particles, then expansion and contraction are inhibited, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into the graphene compound application step: particle fixation, structural reinforcement, and interface improvement are all achieved through the same graphene coating process, reducing overall manufacturing complexity despite the added material step
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 results in an all-solid-state battery with improved safety, reduced interface resistance, and inhibited micro short circuits, enhancing the battery's operational stability and safety by relieving stress on the electrodes and preventing abnormal heating.
Implementation Method 1
a negative electrode active material particle or a plurality of negative electrode active material particles are bound or fixed using a graphene compound
Implementation Method 2
surround solid electrolyte interfaces, and enhance conductivity, preventing expansion and contraction, and reducing the risk of micro short circuits by forming a conductive path
Implementation Method 3
Carrier ions, e.g., lithium ions, pass through a graphene compound, and thus the graphene compound does not hinder the transfer of lithium ions between the positive electrode and the negative electrode in charging or discharging
Data Source
AI summary
Use of silicon as a negative electrode active material particle causes a problem of expansion and contraction of the negative electrode active material particle due to charging and discharging. A negative electrode active material particle or a plurality of negative electrode active material particles are bound or fixed using a graphene compound to inhibit expansion and contraction of the negative electrode active material particle due to charging and discharging. In an all-solid-state secondary battery, an interface between a solid electrolyte and a negative electrode or an interface between the solid electrolyte and a positive electrode has the highest resistance. In order to reduce the interface resistance, at least the negative electrode active material particle is surrounded by a graphene compound to increase the conductivity. Alternatively, a positive electrode active material particle is surrounded by a graphene compound to increase the conductivity. Carrier ions, e.g., lithium ions, pass through a graphene compound, and thus the graphene compound does not hinder the transfer of lithium ions between the positive electrode and the negative electrode in charging or discharging.