Self-Supporting Carbon Electrodes for High Power Energy Storage
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Solution Overview
Problem
Conventional lithium-ion batteries achieve high power performance at the expense of cell robustness and safety, and existing energy storage devices fail to meet the demands of high energy and power density, long cycle life, compact size, light weight, and operational safety for next-generation applications.
Innovation Solution
Development of self-supporting, binder-free carbon electrodes made from nanostructured carbon materials such as oxidized few-walled carbon nanotubes and graphene, which are synthesized using a simple filtration process to control the extent of oxidation and enhance electrical properties and surface chemistry, allowing for high energy and power performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional lithium-ion batteries use high power performance design, then power capability is improved (>50 kW/kg), but cell robustness and safety deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrode materials, specifically using lithium-rich layered oxide cathodes with excess lithium atoms and disordered rock-salt surface layers. This parameter change enables the battery to achieve high power density while maintaining safety and robustness, resolving the contradiction between power capability and reliability.
Solution Approach 2:
The patent employs composite material structures combining lithium-rich layered oxide with disordered rock-salt surface layers, and uses carbon-coated silicon anodes. These composite materials provide both high power performance and enhanced safety/robustness, simultaneously achieving the conflicting requirements of high power capability and improved reliability.
2Use of energy by moving object
If lithium-ion batteries achieve high gravimetric energy density (~200 Wh/kg), then energy storage capacity is improved, but power performance capability deteriorates
Solution Approach 1:
The patent modifies the cathode material parameters by creating lithium-rich compositions with excess lithium and specific crystal structure arrangements. These parameter changes enable the battery to achieve both high gravimetric energy density and high power output, overcoming the traditional trade-off between energy density and power performance.
3Use of energy by moving object
If existing energy storage devices are designed for high energy density, then energy storage capacity is improved, but power capability and cycle life deteriorate
Solution Approach 1:
The patent uses composite material systems including lithium-rich layered oxide cathodes with disordered rock-salt surfaces and carbon-coated silicon anodes. These composites provide high energy density while maintaining excellent power capability and long cycle life, resolving the contradiction between energy density and the combination of power capability with cycle life.
4Use of energy by moving object
If binder-free carbon electrodes are used, then device weight is reduced and energy density is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs self-assembling carbon nanotube networks that automatically form conductive frameworks and self-supporting electrode structures without requiring external binders or complex assembly processes. This self-service mechanism simplifies manufacturing while achieving high energy density, resolving the contradiction between energy density improvement and manufacturing complexity.
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 carbon electrodes achieve high gravimetric energy density (~250 Wh/kg) and high power capability (~1 kW/kg), with improved mechanical integrity and safety, making them suitable for advanced energy storage applications like load-leveling and electrified propulsion.
Implementation Method 1
The carbon electrodes can be made by a simple filtration process from nanostructured carbon materials such as oxidized few-walled carbon nanotubes (FWNTs), oxidized multi-walled carbon nanotubes (MWNTs), and oxidized graphene.
Implementation Method 2
Oxygen functional groups in the nanostructured carbon can undergo Faradaic reactions with lithium ions in lithium cells.
Data Source
AI summary
A self-supporting carbon electrode can include, or consist essentially of, nanostructured carbon, for example, oxygen-functionalized nanostructured carbon.