Silane-Coated Negative Electrode for Aqueous Secondary Battery
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Solution Overview
Problem
Secondary batteries using aqueous electrolyte solutions face challenges with narrow potential windows and unstable operation at high voltages, leading to inadequate self-discharge characteristics and rapid charge/discharge limitations.
Innovation Solution
Incorporating a silane coupling agent and additives such as alkaline earth metal salts, dicarboxylic acids, or organic carbonates into the electrolyte solution to suppress reductive decomposition and enhance the stability of the negative electrode active material, forming a robust and lithium-ion conductive coating that reduces self-discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aqueous electrolyte solution is used to improve safety and reduce flammability, then safety is improved, but the potential window becomes narrow and stable operation at high voltage cannot be achieved
Solution Approach 1:
The patent changes the chemical parameters of the aqueous electrolyte by adding specific additives (alkaline earth metal salts, dicarboxylic acids, carboxylic anhydrides, or organic carbonates) to extend the potential window and enable stable operation at higher voltages while maintaining the safety benefits of water-based electrolytes
Solution Approach 2:
The patent introduces a silane coupling agent as an intermediary substance that forms a coating on the negative electrode active material surface. This coating acts as a mediator between the aqueous electrolyte and the electrode, preventing direct harmful interactions while allowing lithium ion transport, thus enabling stable high-voltage operation
2Reliability
If an aqueous electrolyte solution is used to improve safety, then safety is improved, but self-discharge characteristics deteriorate
Solution Approach 1:
The silane coupling agent forms an intermediary coating layer on the negative electrode that prevents direct contact between the aqueous electrolyte and the electrode active material. This intermediary layer blocks the electrochemical reactions causing self-discharge while maintaining lithium ion conductivity, thus reducing energy loss without compromising safety
Solution Approach 2:
The patent modifies the electrolyte composition by adding specific additives that change the electrochemical parameters of the aqueous solution, reducing its reactivity and self-discharge tendency while maintaining safety characteristics
3Quantity of substance
If an organic-solvent-based electrolyte solution is used to achieve high energy density, then energy density is improved, but flammability increases and safety deteriorates
Solution Approach 1:
The patent changes the fundamental parameter of electrolyte composition from organic solvents to aqueous-based electrolytes with specific additives, maintaining high energy density through optimized lithium salt concentration and additive selection while eliminating flammability risks associated with organic solvents
4Reliability
If an aqueous electrolyte solution is used to improve safety, then safety is improved, but ion conductivity decreases and rapid charge/discharge characteristics cannot be attained
Solution Approach 1:
The patent optimizes the concentration parameters of lithium salts and additives in the aqueous electrolyte to enhance ion conductivity. By carefully adjusting the composition ratios and concentrations, the patent achieves rapid charge/discharge characteristics while maintaining the safety advantages of water-based electrolytes
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 solution effectively suppresses self-discharge and improves the charge/discharge efficiency by forming an electrochemically stable coating that prevents water permeation and enhances lithium ion occlusion and release, allowing for more stable operation at higher voltages.
Implementation Method 1
a coating resulting from reductive decomposition of a silane coupling agent is formed on a surface of the negative electrode active material
Implementation Method 2
a lithium ion secondary battery is widely used, which includes a positive electrode, a negative electrode, and an electrolyte solution and which performs charging/discharging by moving lithium ions between the positive electrode and the negative electrode
Data Source
AI summary
A secondary battery which comprises a positive electrode, a negative electrode, and an electrolytic solution, wherein the electrolytic solution comprises water, a lithium salt, and an additive, the additive including at least one of alkaline-earth metal salts, dicarboxylic acids, carboxylic anhydrides, and organic carbonates, and the negative electrode comprises a negative active material, the negative active material having a silane coupling agent adherent to the surface thereof.