Silver-Doped Sulfide Solid Electrolyte for Dendrite-Resistant Batteries
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Solution Overview
Problem
Conventional all-solid-state batteries face challenges with lower energy density due to the higher specific gravity of solid electrolytes compared to liquid electrolytes, and they suffer from reduced lifespan and durability due to uneven lithium precipitation and dendrite formation.
Innovation Solution
A sulfide-based solid electrolyte doped with silver is developed, which has a novel composition represented by the chemical formula Lia-bMbPcSdXe, where M includes silver and other alkali metals, and X includes halogens, optimizing ion conductivity and preventing dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a negative-electrode-free all-solid-state battery is used to increase energy density, then energy density is improved, but lithium precipitation becomes uneven and dendrites form, reducing lifespan and durability
Solution Approach 1:
A lithium alloy coating layer comprising Li-M (where M is at least one of alkali metals, alkaline earth metals, or transition metals) is introduced as an intermediary between the positive electrode and the sulfide-based solid electrolyte. This coating layer acts as a mediator that promotes uniform lithium ion distribution and prevents direct contact between lithium and the solid electrolyte, thereby preventing dendrite formation while maintaining high energy density
Solution Approach 2:
The lithium alloy coating layer is formed in advance on the positive electrode before assembling the battery. This preliminary action ensures that lithium ions are uniformly distributed and deposited on the coating layer during initial charging, creating a stable foundation that prevents uneven precipitation and dendrite formation during subsequent charge-discharge cycles
2Reliability
If silver is doped into the sulfide-based solid electrolyte to improve ion conductivity, then ion conductivity is improved, but the crystal structure changes
Solution Approach 1:
Silver is doped into the sulfide-based solid electrolyte at controlled concentrations (0.01 to 0.50 mole ratios relative to Li), which modifies the crystal structure parameters and enhances ion conductivity. The doping level is precisely controlled to achieve optimal conductivity while maintaining structural stability
Solution Approach 2:
The solid electrolyte is designed as a composite material combining sulfide-based base material with silver dopant, creating a heterogeneous structure that leverages the high ionic conductivity of silver while maintaining the structural framework of the sulfide material. This composite approach allows simultaneous optimization of conductivity and structural properties
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 sulfide-based solid electrolyte with silver doping ensures uniform lithium formation and removal, preventing dendrite formation, thereby enhancing the lifespan and durability of all-solid-state batteries.
Implementation Method 1
a negative-electrode active material layer of the all-solid-state battery is generally made of a mixture of the negative-electrode active material with a solid electrolyte to secure ion conductivity
Implementation Method 2
Lia-bMbPcSdXe wherein M includes at least one selected from the group consisting of Ag, Na, K, Rb, Cs, Fr, and a combination thereof
Data Source
AI summary
Disclosed are a sulfide-based solid electrolyte doped with silver to have a novel composition, and an all-solid-state battery including the same.According to one aspect of the present disclosure for achieving the above-described technical purpose, there is provided a sulfide-based solid electrolyte comprising a compound represented by a following Chemical formula 1:Lia-bMbPcSdXe [Chemical formula 1]wherein M includes at least one selected from the group consisting of Ag, Na, K, Rb, Cs, Fr, and a combination thereof, wherein X includes at least one selected from the group consisting of F, Cl, Br, I, and combinations thereof, wherein 0<a≤15, 0.02≤b≤0.9, 0≤c≤3, 0<d≤12, and 0≤e≤3.