New insights into the relationship between capacity fading and sulfur loading and electrolyte/sulfur ratio obtained from Li–S pouch cell

High-energy density lithium-sulfur (Li–S) cells have been greatly studied due to the urgent requirements for advanced energy storage applications. During the past decades, many achievements have been obtained through great fundamental researches for inhibiting the shuttle effect, especially including designing various cathode materials and interlayers. As a result, the prepared coin cells in the references deliver a superior long-term cycling performance even for 1000 cycles. However, when facing the practical application of Li–S pouch cells, the poor cycle performance is still existed. This indicates that there is wide gap of scientific knowledge between the fundamental research and the application need. Herein, Li–S pouch cells are designed and used for exploring the key factors that influence the cycle life of the Li–S cell. We mainly discuss the influences of sulfur loading and electrolyte/sulfur ratio on the capacity contribution and cycle life. Combining electrochemical cycle performance and analysis for the Li–S pouch cells after dismantling, we propose two different capacity fading mechanisms for Li–S pouch cells with different E/S ratio (3, 10) and sulfur loading (5.8 mg cm−2, 10.8 mg cm−2). In all, this work provides new understandings into the relationship between capacity fading and sulfur loading and electrolyte/sulfur ratio. This is beneficial for developing practical Li–S cell with high-energy density far exceed the traditional Li-ion cell.