Sulfide Solid Electrolyte Composition for Low-Resistance Sodium Batteries
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Solution Overview
Problem
Sodium all-solid secondary batteries with solid electrolytes face challenges such as increased interfacial resistance, overvoltage, and defects during manufacturing and charging/discharging, leading to potential short circuits and deterioration of battery performance.
Innovation Solution
A sulfide solid electrolyte represented by Formula 1: Na3±xP1−(y1+y2)Wy1My2S4−zXz, where M is a trivalent or tetravalent element, X is a halogen atom, and specific compositional ranges are defined, is used to reduce interfacial resistance and suppress side reactions between sodium metal and the solid electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in sodium batteries, then safety is improved (lower risk of overheating and fire), but interfacial resistance between cathode and solid electrolyte increases during charging and discharging
Solution Approach 1:
The patent modifies the chemical composition parameters of the solid electrolyte by incorporating specific ratios of Na3PS4, Na2SiO3, and P2S5, along with controlled amounts of water (0.1-10 wt%). This compositional parameter adjustment optimizes the electrolyte's properties to reduce interfacial resistance while preserving the safety advantages of solid electrolytes.
Solution Approach 2:
The patent creates a composite solid electrolyte system by combining multiple materials (Na3PS4, Na2SiO3, P2S5) in specific proportions. This composite approach allows the electrolyte to simultaneously achieve low interfacial resistance and high safety performance, resolving the contradiction between these two properties.
2Reliability
If solid electrolyte is used, then safety is improved, but defects and cracks form during manufacturing and charge/discharge processes
Solution Approach 1:
The patent introduces water content as a critical manufacturing parameter, specifying 0.1-10 wt% water in the solid electrolyte composition. This parameter control prevents excessive cracking and defects during manufacturing and battery operation, while maintaining the inherent safety benefits of solid electrolytes.
Solution Approach 2:
The patent proactively addresses potential cracking issues by pre-incorporating controlled amounts of water and specific compositional ratios into the solid electrolyte before battery assembly. This beforehand preparation prevents crack formation during subsequent manufacturing and charge/discharge cycles, ensuring both safety and manufacturing quality.
3Reliability
If solid electrolyte is used, then safety is improved, but side reactions between sodium metal and solid electrolyte increase during charging and discharging
Solution Approach 1:
The patent adjusts the chemical composition parameters of the solid electrolyte, specifically the ratios of Na3PS4, Na2SiO3, and P2S5, along with controlled water content. These parameter modifications reduce the electrochemical instability of the solid electrolyte, thereby suppressing side reactions with sodium metal during battery operation while preserving safety advantages.
Solution Approach 2:
The composite solid electrolyte system combines materials with complementary properties that collectively reduce electrochemical instability. The specific composition (Na3PS4, Na2SiO3, P2S5 in defined ratios with 0.1-10 wt% water) creates a more stable interface with sodium metal, suppressing harmful side reactions while maintaining the safety benefits of solid electrolyte technology.
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 use of the sulfide solid electrolyte with improved ionic conductivity and stability decreases interfacial resistance, suppresses side reactions, and enhances the cycling performance of sodium all-solid secondary batteries.
Implementation Method 1
a sulfide solid electrolyte is represented by Formula 1: Na3±xP1−(y1+y2)Wy1My2S4−zXz
Implementation Method 2
suppresses side reactions between an anode and a solid electrolyte layer
Data Source
AI summary
A sulfide solid electrolyte represented by Formula 1 and a sodium all-solid secondary battery including the same:Na3±xP1−(y1+y2)Wy1My2S4−zXz Formula 1wherein in Formula 1, M may be a trivalent element, a tetravalent element, or a combination thereof, X is a halogen atom, or a combination thereof, 0≤x≤1, 0<y1≤50.5, 0≤z≤1, and 0≤y2≤0.5, wherein if z=0, y2 is not 0.