Sodium-Nickel Chloride Cathode Composition for High Current Capacity
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Solution Overview
Problem
Sodium-nickel chloride batteries face challenges in maintaining performance and cycle life when subjected to high currents, particularly in applications like hybrid locomotives and plug-in electric vehicles, as existing additives do not significantly improve working capacity or reduce capacity degradation.
Innovation Solution
A cathode composition incorporating electroactive metals, a specific alkali metal halide, an electrolyte salt with a low melting point, and a metal chlorosulfide compound, which enhances working capacity and reduces degradation, is introduced. This composition includes metals like titanium, vanadium, and nickel, along with a metal chlorosulfide compound having the formula M1M2p+1SnCl4+3p−2n, improving the battery's performance under high current conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small amounts of conventional additives (sodium iodide, sodium fluoride, elemental sulfur, etc.) are added to the cathode composition, then the battery structure remains simple, but the working capacity is not substantially increased and capacity degradation is not minimized in high current applications
Solution Approach 1:
The patent changes the chemical composition parameters of the cathode by introducing metal chlorosulfide compounds with specific formulas (M1M2p+1SnCl4+3p−2n) and controlling the ratio of additives to cathode materials within 0.1-10 weight percent. This parameter optimization resolves the contradiction by achieving both improved capacity retention and enhanced working capacity through precise compositional control
Solution Approach 2:
The patent creates a composite cathode material by combining conventional cathode materials (nickel, iron, cobalt, etc.) with metal chlorosulfide compounds and alkali metal halides. This composite approach enables synergistic effects where the chlorosulfide compound improves capacity degradation resistance while the electroactive metals maintain high working capacity, resolving the technical contradiction
2Power
If the battery is designed for high current applications (hybrid locomotives, plug-in electric vehicles), then power output is improved, but fuel economy and electric efficiency decrease due to reduced discharged to charged energy ratio
Solution Approach 1:
The patent optimizes the chemical composition parameters of the cathode by incorporating metal chlorosulfide compounds and controlling additive ratios, which improves the battery's ability to tolerate power surges while maintaining efficient energy conversion. The specific compositional parameters enable high current operation with reduced energy loss
Solution Approach 2:
The patent uses small amounts (0.1-10 weight percent) of metal chlorosulfide compound additives that act as performance enhancers. These small quantities provide significant improvement in power tolerance and efficiency without substantially increasing cost or complexity, enabling the battery to achieve better fuel economy via regenerative braking
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 proposed cathode composition significantly enhances the working capacity and decreases capacity degradation of sodium-nickel chloride batteries, particularly under high current applications, by using a sulfur source that improves electrochemical performance and stability.
Implementation Method 1
a cathode composition for an energy storage device... at least one electroactive metal... a metal chlorosulfide compound... which enhances working capacity and reduces degradation
Implementation Method 2
an electrolyte salt comprising a reaction product of a second alkali metal halide and a metal halide, wherein the electrolyte salt has a melting point of less than about 300 degrees Centigrade
Data Source
AI summary
A cathode composition is provided. The cathode composition includes at least one electroactive metal, wherein the electroactive metal is at least one selected from the group consisting of titanium, vanadium, niobium, molybdenum, nickel, iron, cobalt, chromium, manganese, silver, antimony, cadmium, tin, lead and zinc; a first alkali metal halide; an electrolyte salt comprising a reaction product of a second alkali metal halide and a metal halide, wherein the electrolyte salt has a melting point of less than about 300 degrees Centigrade; and a metal chlorosulfide compound having a formula (I) M1M2p+1SnCl4+3p−2n wherein “M1” is a metal selected from group IA of the periodic table, “M2” is a metal selected from group IIIA of the periodic table, “p” is 0 or 1, and “n” is equal to or greater than 0.5. An article and an energy storage device comprising the cathode composition is provided. A method of forming the energy storage device is provided.