Hydrogel Aqueous Electrolyte for Wide-Window Li-S Batteries
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Solution Overview
Problem
Aqueous electrolytes face challenges in supporting high-energy cathode and anode materials due to the narrow electrochemical stability window of water, leading to safety concerns and low energy densities in lithium-ion batteries, while non-aqueous electrolytes pose safety hazards and high costs.
Innovation Solution
Development of an electrolyte system comprising metal salts and hydrophilic polymers in an aqueous solvent, specifically using LiTFSI and LiOTf with poly(vinyl alcohol), which supports a wide electrochemical stability window and suppresses polysulfide shuttling, enabling high-capacity sulfur cathodes and lithium metal anodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If non-aqueous electrolytes are used in lithium-ion batteries, then energy density is improved, but safety and environmental performance deteriorate
Solution Approach 1:
The patent changes the fundamental parameter of electrolyte composition from non-aqueous to aqueous, achieving 100% water content electrolytes that eliminate safety hazards while maintaining operational voltage through advanced electrode material design and surface engineering
Solution Approach 2:
The patent employs composite electrode structures with protective coatings and engineered interfaces that enable aqueous electrolytes to support high-voltage operation, combining multiple materials to achieve both safety and energy density requirements
2Object-affected harmful factors
If aqueous electrolytes are used in lithium-ion batteries, then safety is improved, but energy density deteriorates
Solution Approach 1:
The patent advances the voltage stability window of aqueous electrolytes from conventional 1.23V to over 3.0V through parameter changes in electrolyte composition and electrode surface properties, enabling energy densities that meet practical applications while maintaining inherent safety
Solution Approach 2:
The patent replaces the traditional mechanical/chemical constraint of water's electrochemical stability limit with engineered surface films and interphase structures that prevent water decomposition, allowing high-voltage operation in aqueous systems
3Reliability
If water-in-salt electrolytes are used to expand stability window, then electrochemical stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts and eliminates complex multi-salt formulations, achieving stable high-voltage aqueous electrolytes using simple single-salt or binary salt systems with conventional manufacturing processes
Solution Approach 2:
The patent employs inexpensive, readily available metal salts and standard aqueous solutions that can be manufactured using conventional battery production techniques, avoiding the need for specialized moisture-free infrastructure
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 system achieves energy densities of 135-200 Wh/kg with improved safety and reduced costs, suitable for large-scale applications like smart-grid storage and automotive power systems.
Implementation Method 1
suppresses polysulfide shuttling
Implementation Method 2
an electrochemical cell comprising: (a) an anode; (b) a cathode; and (c) an electrolyte
Data Source
AI summary
The present invention is directed to aqueous electrolytes that comprise at least one metal salt and at least one polymer. The present invention is also directed to methods of making the electrolyte materials and methods of using the electrolyte materials in batteries and other electrochemical technologies.