Role of Polysulfides in Self-Healing Lithium-Sulfur Batteries

摘要

In this work, a novel electrolyte was developed to solve the cycling instability and inefficiency that are inherent to the Li-S battery, which otherwise is a very promising energy storage technology. The sulfur cathode in the current Li-S battery offers superior theoretical capacity (1672 mAh-g~(-1)) compared to all Li-ion battery cathodes (300 mAh-g~(-1) maximum). This high capacity is the result of the redox process [S_8 + 16Li~+ + 16e~- 8Li_2(⇔)S] in the Li-S cell. Therefore, a full Li-S battery could, in theory, deliver an energy density of 2500 Wh-kg~(-1), which is more than twice that of any secondary batteryMoreover, a Li-S battery has the advantages of using an abundant, nontoxic and low-cost cathode materials, as well as having a wide operating temperature range. Despite these advantages, much work is required to address several performance-related issues, which prevent the development of practical Li-S batteries.