Solid Electrolyte Sintering for Low-Temperature Lithium-Ion Transport
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Solution Overview
Problem
Current solid state batteries require increased lithium ionic conductivity for effective performance, particularly at low temperatures, as existing materials do not adequately support fast charging below 0°C.
Innovation Solution
A method for producing a solid electrolyte material with the chemical formula XM2(PS4)3, where X is Li, Na, Ag, or Mg0.5, and M is Ti, Zr, Ge, Si, Sn, or a mixture with Al, involving mixing and sintering powders at specific conditions to achieve enhanced ionic conductivity, resulting in a crystallographic structure that allows for increased lithium ion mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid electrolyte materials are used, then the battery structure is simple, but the lithium ionic conductivity is insufficient for fast charging at low temperatures
Solution Approach 1:
The patent changes the sintering parameters by extending the holding time at the sintering temperature to 75-500 hours, which fundamentally alters the material formation process. This extended time parameter enables the development of the specific orthorhombic crystal structure with space group Fddd, achieving high lithium ionic conductivity (diffusion coefficient ≥3.0×10^-12 m²/s at -20°C) that cannot be obtained through conventional shorter sintering processes.
Solution Approach 2:
The patent employs composite material strategy by forming a specific crystal structure composed of PS4 tetrahedra and MS6 octahedra that assemble into a three-dimensional framework. This composite structural arrangement creates optimized ion transport pathways, achieving high ionic conductivity while maintaining structural stability at low temperatures.
2Reliability
If sintering time is extended to 75-500 hours, then the lithium ionic conductivity increases, but the production time and energy consumption increase
Solution Approach 1:
The patent identifies and optimizes the sintering holding time parameter within the specific range of 75-500 hours at the sintering plateau temperature. This parameter optimization achieves the critical transformation to the orthorhombic phase with high ionic conductivity, balancing the trade-off between extended processing time and achieved material performance.
Solution Approach 2:
The patent focuses the extended sintering process on achieving specific local crystallographic quality - the orthorhombic structure with space group Fddd and specific peak intensity ratios ((IA-IB)/(IA+IB) > 0). This localized structural quality enhancement at critical crystallographic positions enables high ionic conductivity without requiring uniform modification throughout the entire material.
3Loss of energy
If the sintering plateau temperature is kept below 500°C, then energy consumption is reduced, but the crystal structure formation may be incomplete
Solution Approach 1:
The patent changes the temperature parameter by maintaining the sintering plateau temperature below 500°C (preferably below 400°C), which reduces energy consumption compared to conventional high-temperature sintering. This temperature parameter optimization is compensated by the extended holding time, allowing sufficient thermal energy accumulation for complete crystal structure formation at lower temperatures.
Solution Approach 2:
The patent applies preliminary action by extending the sintering holding time before final cooling, allowing the crystal structure to fully develop and stabilize at the lower sintering temperature. This preliminary structural formation ensures complete phase transformation and optimal crystal quality is achieved before the material is removed from the sintering process.
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 method increases lithium ionic conductivity, enabling fast charging of batteries, especially at low temperatures, by forming a 3D framework structure with PS4 tetrahedra and MS6 octahedra, and improves electrochemical stability with the inclusion of aluminum, resulting in a diffusion coefficient of lithium exceeding 3.0·10−12 m2/s at −20°C.
Implementation Method 1
sintering the powder mixture for a period of time equal to or greater than 75 hours and equal to or smaller than 500 hours at a sintering plateau temperature
Implementation Method 2
exhibiting peaks in positions of 2θ=13.64° (±1°), 16.48° (±1°) and 22.18° (±1°) in a X-ray diffraction measurement using CuKα line
Data Source
AI summary
A method for producing a solid electrolyte for an all-solid state battery, the solid electrolyte having the following chemical formula XM2(PS4)3, where X is lithium (Li), sodium (Na), silver (Ag) or magnesium (Mg0,5) and M is titanium (Ti), zirconium (Zr), germanium (Ge), silicon (Si), tin (Sn) or a mixture of X and aluminium (X+Al) and the method including: mixing powders so as to obtain a powder mixture; pressing a component with powder mixture; and sintering component for a period of time equal to or greater than 100 hours so as to obtain the solid electrolyte. The solid electrolyte exhibits the peaks in positions of 2θ=13.64° (±1°), 13.76° (±1°), 14.72° (±1°), 15.36° (±1°), 15.90° (±1°), 16.48° (±1°), 17.42° (±1°), 17.56° (±1°), 18.58° (±1°), and 22.18° (±1°) in a X-ray diffraction measurement using CuKα line. The disclosure is also related to a method of producing a solid electrolyte.