High-Performance All-Solid-State Lithium/Sulfur Batteries Achieve 1080 mAh/g Capacity Retention After 50 Cycles with Br-Doped Lithium Argyrodite Electrolyte

June 28, 2026

ResearchGate Unknown

Overview

Research from ResearchGate demonstrates the potential of high-performance all-solid-state lithium/sulfur batteries utilizing Br-doped lithium argyrodite electrolytes. These batteries achieved a maximum initial capacity of 1460 mAh/g and maintained an excellent reversible capacity of up to 1080 mAh/g after 50 cycles at a C/10 rate. Ex situ X-ray diffraction confirmed the structural stability of Li6PS5Br during cycling, indicating a promising pathway to safer and longer-lasting batteries by replacing hazardous organic electrolytes.

In Depth

Key Findings

High-performance all-solid-state lithium/sulfur (Li/S) batteries utilizing lithium argyrodite electrolytes, particularly Br-doped variants, have demonstrated exceptional electrochemical performance. These batteries achieved a maximum initial discharge capacity of 1460 mAh/g and sustained a remarkable reversible capacity of up to 1080 mAh/g after 50 cycles at a C/10 rate. This breakthrough highlights the potential for significantly safer and longer-lasting batteries by effectively replacing hazardous organic liquid electrolytes.

Technical / Clinical Details

The study focused on enhancing the performance of all-solid-state Li/S batteries by employing highly conductive lithium argyrodite solid electrolytes. Specifically, Br-doped and Cl-doped Li6PS5X (where X = Br, Cl) electrolyte variants were synthesized and their characteristics thoroughly compared. The batteries were constructed using a lithium metal anode and a sulfur cathode, typical components for high-energy Li/S systems, and their electrochemical properties were rigorously evaluated.

High Initial Capacity: Cells employing the Br-doped lithium argyrodite electrolyte exhibited a very high initial discharge capacity of 1460 mAh/g, closely approaching the theoretical capacity of sulfur (1675 mAh/g).
Excellent Cycling Stability: At a moderate C/10 charge-discharge rate, the batteries maintained a high reversible capacity of 1080 mAh/g after 50 cycles, corresponding to a capacity retention of approximately 74% relative to the initial capacity. This performance surpasses many existing Li/S battery systems.
Electrolyte Structural Stability: Ex situ X-ray diffraction (XRD) analysis confirmed that the crystal structure of the Li6PS5Br electrolyte remained remarkably stable throughout the cycling process. This structural integrity is crucial for preventing electrolyte degradation and ensuring long-term battery performance.
Enhanced Safety: By replacing flammable organic liquid electrolytes with a solid electrolyte, the inherent safety of the battery is significantly improved, drastically reducing the risk of thermal runaway and fire hazards.

These results collectively indicate that Li argyrodite solid electrolytes are highly promising materials for realizing all-solid-state Li/S batteries that offer both high energy density and excellent cycle life.

Background & Context

Lithium/sulfur batteries are considered one of the most promising next-generation battery technologies due to their exceptionally high theoretical energy density (up to 2500 Wh/kg), making them attractive for electric vehicles and portable electronics. However, conventional Li/S batteries with liquid electrolytes suffer from critical issues such as the polysulfide shuttle effect and lithium dendrite formation, which severely limit their cycle life and safety. The transition to all-solid-state architecture offers a potent solution to these problems, unlocking the full potential of Li/S chemistry. Sulfide-based solid electrolytes, in particular, have gained significant attention as core technologies for all-solid-state Li/S batteries due to their high ionic conductivity and favorable mechanical properties. This research specifically validates the high compatibility of the Li argyrodite system with Li/S chemistry, thereby accelerating further advancements in the field.

Strategic Significance & Outlook

The demonstrated superior performance of all-solid-state Li/S batteries with Br-doped Li argyrodite electrolytes signifies a major step forward towards their practical implementation. Future efforts will likely focus on further optimization, including improving cathode material design, reducing interfacial resistance, and evaluating performance at higher charge-discharge rates to achieve even greater energy densities and extended cycle lives. Additionally, cost reduction strategies for electrolyte synthesis and the development of large-scale manufacturing techniques will be critical for commercialization. This breakthrough has the potential to accelerate the adoption of electric vehicles by extending driving ranges and provides a promising solution for efficient renewable energy storage, positioning all-solid-state Li/S batteries as a key enabler for a sustainable energy future.

Source: https://www.researchgate.net/publication/276398642_High_performance_all-solid-state_lithiumsulfur_batteries_using_lithium_argyrodite_electrolyte

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