Anode-Free Sodium Metal Battery With Non-Porous Sodium Plating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Anode-free sodium metal full cells face challenges with dynamic interfacial stability, leading to surface roughness, dendritic growths, and short cycle life due to irreversible solid electrolyte interphase (SEI) layers and heterogeneous ionic flux, which undermines Coulombic efficiency and capacity retention.
Innovation Solution
A rechargeable anode-free sodium metal battery design featuring a cathode substrate with nanomaterial, a non-aqueous electrolyte with low water content, and an anode substrate where sodium metal is deposited during recharge to form a continuous, shiny-smooth, non-porous ingot-type surface, preventing SEI accumulation and maintaining interfacial stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional non-aqueous electrolytes are used in anode-free sodium metal batteries, then sodium metal can be deposited and stripped, but irreversible SEI layers accumulate leading to low Coulombic efficiency and short cycle life
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using specific glyme-based solvents (diglyme, triglyme, or tetraglyme) with sodium salts (NaPF6, NaBF4, or NaClO4) at controlled concentrations (0.5-2.0 M), which fundamentally alters the SEI formation behavior to be reversible rather than irreversible, thereby simultaneously improving cycle life and Coulombic efficiency
Solution Approach 2:
The patent employs a composite electrolyte system combining glyme-based solvents with specific sodium salts, creating a synergistic effect where the glyme solvent provides flexible solvation and the sodium salts form stable, reversible SEI components, achieving superior electrochemical performance that neither component could achieve alone
2Stability of the object's composition
If glyme-based electrolytes are used with excess sodium metal or complex current collectors, then dynamic interfacial stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the unnecessary components (excess sodium metal and complex current collector structures) from the system, demonstrating that simple copper or aluminum current collectors are sufficient when paired with the optimized glyme-based electrolyte, thereby reducing device complexity while maintaining interfacial stability
Solution Approach 2:
The patent enables the simple current collector to serve itself by forming stable, reversible SEI layers directly on its surface through the glyme-based electrolyte, eliminating the need for additional protective coatings or complex structural designs, thus achieving self-stabilization of the interface
3Productivity
If conventional electrolytes are used, then sodium metal deposition occurs, but heterogeneous ionic flux promotes dendritic growths causing internal shorts
Solution Approach 1:
The patent changes the physical and chemical parameters of the electrolyte environment by using glyme-based solvents with specific viscosity, dielectric constant, and solvation properties, which homogenize the ionic flux distribution during sodium deposition, preventing localized concentration gradients that lead to dendritic growth while maintaining high deposition rates
Solution Approach 2:
The patent achieves homogeneous ionic flux distribution through the unique solvation properties of glyme-based electrolytes, which ensure uniform sodium ion transport to the electrode surface, eliminating the heterogeneous flux conditions that promote dendritic nucleation and growth
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 achieves a capacity retention rate of 99.93% per cycle and near-theoretical Coulombic efficiency, surpassing existing anode-free Na and Li batteries, with no repeated SEI formation and stable interfacial impedance, enabling high-performance anode-free full cells.
Implementation Method 1
sodium metal is deposited during recharge to form a continuous, shiny-smooth, non-porous ingot-type surface
Implementation Method 2
allowing Na ion to diffuse across and complete the electroplating process
Data Source
AI summary
The present disclosure is directed to a rechargeable anode-free sodium metal battery including: a cathode substrate; a cathode nanomaterial deposited onto the cathode substrate; a nonaqueous electrolyte, wherein a total water content of the non-aqueous electrolyte is about 10 ppm or less; and an anode substrate, wherein the anode substrate has no deposited material prior to battery recharge, and wherein the anode substrate comprises an ingot-type, non-porous sodium metal surface formed during battery recharge.