Cross-Linked Polymer Gel Electrolyte for Wider Aqueous Battery Voltage
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Solution Overview
Problem
Aqueous batteries face a narrow electrochemical stability window due to the use of water as a solvent, limiting their operating potential and energy density, and existing polymer gel electrolytes do not effectively extend the voltage range beyond 2.4 volts.
Innovation Solution
A chemically cross-linked copolymer gel electrolyte composed of acrylamide, [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) monomers, and N,N′-methylenebisacrylamide, which forms a quasi-solid gel structure to trap aqueous electrolytes, providing high ionic conductivity and electrochemical stability, allowing operation up to 2.6 volts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water is used as solvent in aqueous batteries, then low cost and non-flammability are achieved, but electrochemical stability window is limited to 1.23 V
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to gel form, and modifies the chemical composition by incorporating zwitterionic groups and cross-linking the polymer matrix. These parameter changes allow the electrolyte to stabilize water at potentials beyond 1.23 V, enabling operation up to 2.4 V while maintaining the inherent safety advantages of aqueous systems
Solution Approach 2:
The patent creates a composite gel electrolyte system combining hydrophilic polymer chains (polyacrylamide), zwitterionic compounds (sulfobetaine derivatives), and cross-linking agents. This composite structure provides both the safety of aqueous electrolytes and the electrochemical stability needed for high-voltage operation, resolving the contradiction between flammability safety and electrochemical stability
2Use of energy by moving object
If operating voltage is increased beyond 1.23 V in aqueous batteries, then energy density is improved, but oxygen evolution reaction occurs reducing stability
Solution Approach 1:
The patent modifies the electrolyte's chemical and physical parameters by introducing zwitterionic groups and cross-linking, which shift the electrochemical stability window to accommodate higher operating voltages (up to 2.4 V) without triggering oxygen evolution, thus enabling high energy density while maintaining stability
Solution Approach 2:
The patent uses cost-effective materials (polyacrylamide, common zwitterionic compounds, simple cross-linkers) to create a gel electrolyte that provides long-term stable operation at high voltages, avoiding the need for expensive alternatives while achieving the desired energy density and stability
3Quantity of substance
If polyacrylamide gel electrolyte is used, then hydrophilicity and water retention are improved, but operating voltage is limited to below 2.4 V
Solution Approach 1:
The patent combines polyacrylamide's hydrophilic properties with zwitterionic compounds and cross-linking agents to create a composite gel structure that simultaneously achieves superior water retention and extended electrochemical stability window, overcoming the voltage limitation of pure polyacrylamide gels
Solution Approach 2:
The patent introduces zwitterionic groups at specific locations within the gel matrix to create local regions of enhanced electrochemical stability, while the bulk polyacrylamide structure maintains overall water retention. This local modification allows the gel to operate at voltages up to 2.4 V without sacrificing water holding capacity
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 cross-linked polymer gel electrolyte enhances the electrochemical stability and ionic conductivity of aqueous batteries, expanding the operating voltage range and enabling stable electrochemical reactions beyond the conventional limit, thus improving energy density and electrode compatibility.
Implementation Method 1
The cross-linked polymer gel structure traps water molecules, resulting in higher electrochemical stability of water, and amide groups improve this trapping ability
Implementation Method 2
these gels have high ionic conductivity and can protect the zinc metal anode
Implementation Method 3
The second component of the copolymer is [2-(Methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl), which has a zwitterionic structure, it contains positive and negative ionic charges in the same polymer backbone. This that provide such advantages as high ion conductivity and powerful water retention ability
Data Source
AI summary
The invention relates to the electrochemical industry, and particularly to polymer gel electrolytes for secondary aqueous batteries.The objective of the invention is to create a chemically cross-linked polymer electrolyte gel for secondary water batteries, which increases the electrochemical stability of water, thereby expanding the operating voltage range.The technical result of the invention is to expand the operating voltage range by means of a chemically cross-linked polymer electrolyte gel for secondary water batteries. It provides high electrochemical stability and high ionic conductivity.This technical result is achieved due to the fact that the invention proposes a cross-linked polymer, which consists of acrylamide (AA), [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) (DMAPS) and N,N′-methylenebisacrylamide (MBA).AA and DMAP are monomers and MBA is a coupling agent. An aqueous solution of an electrolyte salt in a crosslinked polymer structure to form a quasi-solid gel electrolyte material. The cross-linked polymer gel electrolyte is designed to be used both as a separator and as an electrolyte. It is placed between the negative (anode) and positive (cathode) electrodes. As a separator, it prevents direct contact of the electrodes, and as an electrolyte, it provides an environment in which ions pass from one electrode to another or from electrode to electrolyte and vice versa. AA amide group, DMAP cationic and anionic groups provide high ionic conductivity and strong water retention capacity in the crosslinked polymer gel electrolyte. The invention, due to its high ionic conductivity, has a high reversibility of the electrochemical reaction and high electrochemical stability due to the retention of water in the hydrophilic structure.