Doped Sulfide Solid Electrolyte for Stable Lithium Anode Interfaces
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Solution Overview
Problem
Lithium argyrodites (LPSC)-type sulfide solid electrolytes face challenges such as poor compatibility with Li metal anode and poor cycle stability, hindering their practical application in next-generation batteries.
Innovation Solution
A sulfide solid electrolyte doped with a VB group element (V, Nb, Ta) and a halogen (F, Cl, Br) is developed, with a chemical composition of Li6P1-a(M)aS5X, which improves compatibility with lithium anodes and maintains a desirable argyrodite crystal phase, enhancing electrochemical stability and cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LPSC-type sulfide solid electrolyte is used, then high ionic conductivity is achieved, but compatibility with Li metal anode deteriorates
Solution Approach 1:
The patent applies local quality by doping specific elements (VB group elements V, Nb, Ta and halogen elements F, Cl, Br) at specific sites within the sulfide solid electrolyte lattice. This selective doping at the atomic level modifies local chemical properties and electronic structure, improving compatibility with Li metal anode while preserving the bulk ionic conductivity of the material.
Solution Approach 2:
The patent changes chemical composition parameters by introducing dopants at controlled concentrations (0.01 ≤ a ≤ 0.2 in Li6P1-a(M)aS5X). This parameter modification alters the electrochemical stability window and interface properties of the electrolyte, enabling better compatibility with Li metal anode while maintaining desirable ionic conductivity through optimized doping levels.
2Reliability
If LPSC-type sulfide solid electrolyte is used, then high ionic conductivity is achieved, but cycle stability deteriorates
Solution Approach 1:
The patent applies local quality by introducing dopants at specific lattice positions to modify local chemical stability and resistance against degradation. The dopanted sites act as stabilizing centers that prevent structural collapse and chemical decomposition during cycling, thereby improving long-term cycle stability while preserving ionic conduction pathways.
Solution Approach 2:
The patent applies preliminary action by pre-doping the sulfide solid electrolyte with VB group and halogen elements before battery assembly. This preliminary modification establishes enhanced chemical stability and structural robustness in advance, preventing degradation reactions during subsequent cycling operations and ensuring long-term cycle stability.
3Adaptability or versatility
If P element is partially replaced by VB group element, then compatibility with lithium anode is improved, but crystal phase stability may deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the doping concentration parameter a within a specific range (0.01 ≤ a ≤ 0.2). This controlled parameter modification ensures that the argyrodite crystal phase stability is maintained while achieving sufficient compatibility improvement with lithium anode. The optimal balance is achieved through precise parameter optimization.
Solution Approach 2:
The patent applies composite materials by creating a doped sulfide solid electrolyte composite with formula Li6P1-a(M)aS5X, where M represents VB group elements. This composite structure combines the base LPSC matrix with dopant atoms, synergistically maintaining crystal phase stability while introducing improved anode compatibility properties through the dopant elements.
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 doped sulfide solid electrolyte exhibits improved air stability, cycle stability, and electrochemical performance, achieving high room-temperature ion conductivity and desirable processability, thus enabling more efficient and stable all-solid-state batteries.
Implementation Method 1
doping of the M element from a VB group could generate a layer of M2O5 on a surface of the sulfide electrolyte
Data Source
AI summary
Provided are a sulfide solid electrolyte, and a preparation method and use thereof. The sulfide solid electrolyte has a chemical composition formula of Li6P1-a(M)aS5X (where M is one or more selected from the group consisting of V, Nb, and Ta, and X is one or more selected from the group consisting of F, Cl, and Br). The preparation method includes: weighing raw materials of a Li source, a P source, an S source, an M source, and an X source, and mixing to be uniform to obtain a mixture, and subjecting the mixture to ball milling to obtain a precursor powder of the sulfide solid electrolyte; sieving the precursor powder to obtain a sieved powder, and then pressing the sieved powder into a solid sheet; and subjecting the solid sheet to vacuum high-temperature sintering to obtain the sulfide solid electrolyte.