Oxysulfide Semi-Solid Electrolyte for Low-Pressure High-Current Cells
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Solution Overview
Problem
Solid-state batteries face limitations in ionic conductivity, current density, and require high stack pressures to maintain contact between electrodes, leading to stress and potential short circuits.
Innovation Solution
A semi-solid electrolyte system combining an oxysulfide solid-state electrolyte and a solvate ionic liquid is introduced, which facilitates ion transfer and reduces stack pressure requirements, enhancing ionic conductivity and chemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high cell stack pressure is applied to sulfide solid-state electrolytes, then ionic conductivity is improved, but chemical stability deteriorates and internal short circuits occur
Solution Approach 1:
The patent employs a composite electrolyte system combining oxysulfide solid-state electrolyte with solvate ionic liquid. The oxysulfide SSE provides structural stability and chemical resistance, while the ionic liquid fills pores and enhances ionic conductivity. This composite approach allows the system to achieve high ionic conductivity without requiring excessive stack pressure that would compromise chemical stability of pure sulfide SSEs.
Solution Approach 2:
The patent applies different material properties to different regions: the oxysulfide SSE matrix provides mechanical strength and chemical stability, while the solvate ionic liquid specifically targets pore regions to enhance ion transport. This localized functional distribution allows the system to optimize both stability and conductivity without uniform pressure application that would harm overall chemical stability.
2Productivity
If high cell stack pressure is applied to achieve high current density, then ion transfer is improved, but internal short circuits occur
Solution Approach 1:
The composite oxysulfide SSE-ionic liquid system provides a stable interface between electrodes and electrolyte. The ionic liquid component forms a compliant interlayer that maintains stable contact at lower pressures, preventing the electrode deformation and dendrite formation that lead to internal short circuits, while still enabling high current density operation.
Solution Approach 2:
The solvate ionic liquid acts as an intermediary layer between the oxysulfide SSE and electrode surfaces. This intermediate phase improves interfacial contact and ion transfer efficiency, enabling high current density without requiring high stack pressure that would cause mechanical failure and short circuits.
3Reliability
If pure sulfide solid-state electrolyte is used, then ionic conductivity can be high, but chemical stability and safety deteriorate
Solution Approach 1:
The patent creates a composite system where oxysulfide SSE provides chemical stability and structural integrity, while solvate ionic liquid enhances ionic conductivity. The oxysulfide composition (containing P2O5 or other oxide formers) inherently provides better chemical stability than pure sulfide SSEs, while the ionic liquid component ensures high ion transport efficiency without compromising safety.
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating oxide formers (P2O5, SiO2, etc.) into the sulfide SSE matrix to create oxysulfide electrolytes. This compositional parameter change fundamentally improves chemical stability while maintaining good ionic conductivity, which is then further enhanced by the ionic liquid additive.
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 semi-solid electrolyte system supports high current densities at low pressures, ensuring excellent ionic conductivity and chemical stability, thereby improving the performance and longevity of solid-state batteries.
Implementation Method 1
The oxysulfide solid-state electrolyte and the solvate ionic liquid are collectively configured for facilitating ion transfer between an anode of the battery cell and a cathode of the battery cell
Implementation Method 2
providing a compliant interlayer that supports high current densities at low stack pressures
Data Source
AI summary
A semi-solid-state electrolyte system for use in a battery cell is provided. The semi-solid-state electrolyte system includes an oxysulfide solid-state electrolyte and a secondary electrolyte including a solvate ionic liquid. The semi-solid-state electrolyte system is configured for providing excellent ionic conductivity, supporting high current densities at a low stack pressure, and including excellent chemical stability. The oxysulfide solid-state electrolyte and the solvate ionic liquid are collectively configured for facilitating ion transfer between an anode of the battery cell and a cathode of the battery cell.