Battery Charge Transfer via Metal Plating
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Solution Overview
Problem
Conventional sodium and lithium-based rechargeable batteries face challenges due to high operating temperatures and chemically reactive catholyte solutions, leading to degradation of solid alkali ion conductive electrolyte membranes and reduced battery life.
Innovation Solution
The implementation of a battery charge transfer mechanism that allows metal plating to form on the positive electrode during discharge and oxidize back into solution during charging, using an alkali metal ion conductive electrolyte membrane and a liquid positive electrode solution containing alkali metal halides or pseudohalides, which helps maintain the membrane's stability and extends battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional sodium or lithium-based rechargeable batteries use high pH catholyte solutions for charge transfer, then charge transfer efficiency is maintained, but the solid alkali ion conductive electrolyte membrane degrades due to chemical reactivity
Solution Approach 1:
The patent changes the pH parameter of the catholyte solution from high pH (conventional) to low pH (acidic), using solutions such as sulfuric acid, hydrofluoric acid, or boric acid. This parameter change allows efficient charge transfer while preventing degradation of the solid alkali ion conductive electrolyte membrane, as the acidic environment is less reactive toward the membrane material.
2Productivity
If batteries operate at high temperatures to maintain ion conductivity, then charge transfer is efficient, but membrane degradation accelerates and battery life decreases
Solution Approach 1:
The patent changes the temperature parameter from high temperature operation (conventional) to lower temperature operation. By using low pH catholyte solutions that prevent membrane degradation, the battery can operate at lower temperatures while maintaining acceptable ion conductivity and extending battery life.
3Reliability
If solid alkali ion conductive electrolyte membranes are used to prevent electrode solution intermixing, then Faradaic efficiency approaches 100%, but the membranes are susceptible to dissolution in reactive catholyte environments
Solution Approach 1:
The patent changes the chemical environment parameter (pH) of the catholyte solution to acidic conditions. This parameter change creates a chemical environment where the solid alkali ion conductive electrolyte membrane is stable and resistant to dissolution, while still maintaining its ion-selective properties and preventing electrode solution intermixing, thus preserving Faradaic efficiency.
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 enhances the Faradaic efficiency and extends the useful life of rechargeable batteries by preventing membrane degradation and maintaining efficient charge transfer processes, while allowing for operation at lower temperatures.
Implementation Method 1
Solid alkali ion conductive electrolyte membranes are used in electrochemical cells... being: ion conductive, ion selective... NaSICON (Na Super Ion CONducting) membranes selectively transport sodium cations
Implementation Method 2
In order to produce electrical energy, batteries typically convert chemical energy directly into electrical energy... During discharge, electrochemical reduction occurs at the cell's positive electrode, while electrochemical oxidation occurs at the cell's negative electrode
Implementation Method 3
During discharge, electrochemical reduction occurs at the cell's positive electrode... metal plating to form on a battery's positive electrode as the battery discharges
Implementation Method 4
as the battery charges, the metal plating oxidizes to release the metal ion back into the positive electrode solution
Data Source
AI summary
The present invention provides a secondary cell having a negative electrode compartment and a positive electrode compartment, which are separated by an alkali ion conductive electrolyte membrane. An alkali metal negative electrode disposed in the negative electrode compartment oxidizes to release alkali ions as the cell discharges and reduces the alkali ions to alkali metal during recharge. The positive electrode compartment includes a positive electrode contacting a positive electrode solution that includes an alkali metal compound and a metal halide. The alkali metal compound can be selected from an alkali halide and an alkali pseudo-halide. During discharge, the metal ion reduces to form metal plating on the positive electrode. As the cell charges, the metal plating oxidizes to strip the metal plating to form metal halide or pseudo halide or corresponding metal complex.