Sodium Battery Liquid Cathode Room Temperature Operation
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Solution Overview
Problem
Existing Na-based secondary batteries face challenges in operating at low temperatures while maintaining high output and charge/discharge speed, due to high operational temperatures and low economic efficiency, which limits their competitiveness compared to lithium and nickel-hydrogen batteries.
Innovation Solution
A Na-based secondary battery design featuring a sodium anode, a liquid-state cathode containing metal halides, and a sodium ion conductive solid electrolyte, allowing for electrochemical reactions to occur at room temperature to 200°C, with the cathode comprising a liquid-state component and a solid-state component, and using a solvent to dissolve metal halides, enhancing charge/discharge speed and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If existing Na-based secondary batteries (sodium-sulfur or sodium-nickel chloride) are used to achieve high energy storage capacity, then the battery can store sufficient energy, but the operation temperature must be maintained at 250-300°C or higher, which increases manufacturing complexity and operating costs
Solution Approach 1:
The patent changes the physical state parameter of the cathode from solid to liquid, and modifies the chemical composition by using metal halides dissolved in solvents instead of traditional sulfur or nickel chloride. This parameter change enables the battery to operate at room temperature while maintaining high energy storage capacity, as the liquid-state cathode provides excellent ionic conductivity and electrochemical activity without requiring high temperatures.
Solution Approach 2:
The patent employs composite materials by combining metal halides (such as nickel halide, copper halide, zinc halide) with specific solvents (ionic liquids, organic solvents, or water) to create a liquid-state cathode. This composite approach leverages the high capacity of metal halides and the conductivity benefits of the solvent system, achieving both high energy storage and low operating temperature requirements simultaneously.
2Temperature
If room-temperature Na-based battery is developed to reduce operation temperature, then the operating temperature can be reduced to room temperature, but the output and charge/discharge speed become significantly low
Solution Approach 1:
The patent changes the cathode from solid to liquid state, which fundamentally improves ionic conductivity and electrochemical reaction kinetics. The liquid-state cathode allows for rapid sodium ion transport and electron transfer, enabling high charge/discharge speeds at room temperature. This parameter change directly addresses the productivity issue by creating a system where ions can move freely and reactions can proceed rapidly without thermal activation.
Solution Approach 2:
The patent adopts the liquid electrolyte concept from lithium-ion batteries and applies it to sodium-based systems. By copying the successful liquid electrolyte approach from lithium technology and adapting it with metal halide solutes, the patent achieves high-rate performance in sodium batteries at room temperature, overcoming the inherent sluggish kinetics of traditional solid-state Na-based systems.
3Quantity of substance
If lithium battery is used to achieve high energy density and output characteristics, then the battery can deliver excellent performance, but the economic efficiency deteriorates due to the scarcity of lithium source
Solution Approach 1:
The patent replaces expensive and scarce lithium with abundant and inexpensive sodium, which is the second most abundant element in the Earth's crust. By using sodium-based chemistry with metal halide cathodes, the patent creates a battery system that achieves lithium-competitive performance at a fraction of the material cost, dramatically improving economic efficiency and ease of manufacture while maintaining high energy density.
Solution Approach 2:
The patent changes the base metal from lithium to sodium, fundamentally altering the chemical system while maintaining similar performance characteristics. The liquid-state cathode design with metal halides compensates for sodium's larger ionic radius and different electrochemical properties, achieving energy densities comparable to lithium batteries but with abundant, low-cost materials, thus resolving the economic efficiency contradiction.
4Productivity
If high temperature operation is maintained to ensure conductivity and reaction rate, then the battery can maintain adequate output, but the sealability and safety of the battery are compromised
Solution Approach 1:
The patent changes the operating temperature parameter from high (250-300°C) to room temperature, which fundamentally improves safety and sealability. The low operating temperature eliminates thermal runaway risks, reduces material degradation, and allows for simpler sealing structures. Meanwhile, the liquid-state cathode with metal halides maintains high conductivity and reaction rates at room temperature, preserving adequate output without requiring high temperature operation.
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 battery operates efficiently at low temperatures, increasing charge/discharge speed and capacity, reducing internal resistance, and maintaining economic advantages by using abundant resources, thus improving its competitiveness with other battery technologies.
Implementation Method 1
a cathode containing metal halide, which is a halide of at least one metal selected from a group consisting of alkali metals, transition metals, and Groups 12 to 14 metals, and a solvent dissolving the metal halide
Implementation Method 2
a sodium ion conductive solid electrolyte separating the cathode and the anode from each other
Implementation Method 3
The Na based secondary battery is charged by a charge reaction according to the following Reaction Formula 1 and discharged by a discharge reaction according to the following Reaction formula 2
Data Source
Figure 1
Figure 2(a)~2(b)
AI summary
Provided is a Na based secondary battery including: an anode containing sodium or a sodium alloy; a cathode containing a metal halide, which is a halide of at least one metal selected from a group consisting of alkali metals, transition metals, and Groups 12 to 14 metals, and a solvent dissolving the metal halide; and a sodium ion conductive solid electrolyte separating the cathode and the anode from each other.