Sodium-Ion Battery Anode Film and Electrolyte for Dendrite Control
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Solution Overview
Problem
Sodium ion batteries face challenges with poor circulation performance due to sodium dendrite growth, which affects their energy density and practical application.
Innovation Solution
A secondary battery design featuring a positive electrode with a sodium ion active material layer, a negative electrode with a metal film layer of specific metals (e.g., aluminum, nickel, chromium) and a sodium borate electrolyte, which inhibits sodium dendrite growth by reducing nucleation overpotential and improving deposition uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sodium ion battery uses metal sodium deposition on negative current collector, then energy density is improved, but sodium dendrites grow and circulation performance deteriorates
Solution Approach 1:
The patent introduces a metal film layer as an intermediary between the negative current collector and the sodium metal deposition. This intermediate layer (comprising metals like Al, Ni, Cr, Bi, Sn, In, or Sb) mediates the sodium deposition process, enabling uniform sodium distribution while preventing dendrite formation. The metal film layer acts as a buffer that reconciles the high energy density requirement with the circulation performance concern.
Solution Approach 2:
The patent changes the physical and chemical parameters of the negative electrode by controlling the metal film layer thickness (10-300 nm) and composition. By adjusting these parameters, the nucleation overpotential is optimized to promote uniform sodium deposition. The electrolyte composition is also modified by adding sodium borate to further control deposition behavior and inhibit dendrite growth.
2Ease of manufacture
If sodium ion battery uses conventional electrolyte, then manufacturing is simple, but sodium deposition is non-uniform and dendrites form
Solution Approach 1:
The patent modifies the electrolyte composition by adding sodium borate to conventional electrolytes. This parameter change in the electrolyte system alters the sodium ion transport and deposition characteristics, resulting in more uniform sodium metal deposition on the negative electrode while maintaining relative manufacturing simplicity.
3Manufacturing precision
If metal film layer thickness is increased, then sodium deposition uniformity is improved, but energy density decreases
Solution Approach 1:
The patent optimizes the metal film layer thickness parameter to a specific range (10-300 nm) to achieve the best balance between deposition uniformity and energy density. This precise parameter control ensures that the metal film layer is thick enough to promote uniform sodium deposition but thin enough to minimize its impact on overall battery energy density.
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 significantly enhances the circulation performance and energy density of sodium ion batteries by preventing sodium dendrite formation and promoting uniform sodium deposition, thereby improving overall battery efficiency.
Implementation Method 1
a nucleation overpotential of sodium on the negative electrode plate is smaller than or equal to 35 mV
Implementation Method 2
the metal film layer has a relatively low overpotential for metal sodium, and cooperates with the sodium borate in the electrolyte, to induce sodium to be uniformly deposited
Implementation Method 3
the electrolyte contains a sodium borate
Data Source
AI summary
Provided is a secondary battery including a positive electrode plate, a negative electrode plate, and an electrolyte. The positive electrode plate includes a positive current collector and a positive active material layer arranged on the positive current collector, and the positive active material layer contains a sodium ion active material. The negative electrode plate includes a negative current collector and a metal film layer arranged on at least one surface of the negative current collector. A nucleation overpotential of sodium on the negative electrode plate is smaller than or equal to 35 mV. The electrolyte is arranged between the positive electrode plate and the negative electrode plate, and the electrolyte contains a sodium borate.