Advanced Cathode, Electrolyte and Separator materials to Improve the Energy Density and Cycle Stability of Soft-Package Lithium-Sulfur Battery

The lithium/sulfur battery has been attracting increasing attention due to their higher theoretical specific energy density (2,600 Wh kg⁻¹), almost ten times greater than that of commercially used lithium ion batteries.  However the practical energy density of the Li/S battery (soft package) is still too low (<450Wh/kg), accompanied other unsolved problems as poor cycle life, low safety as well as worse rate capability.  In order to solve these problems, we need to develop better cathode materials, better electrolyte composition, better anode protect mechanism and ect.

In our lab, we mainly focus on the study of cathode materials (carbon/sulfur), cathode structure, electrolyte and separators, which combined together to improve the battery performance.      For one thing, by improving the cathode (including the carbon surface area, C/S ratio, porous distribution), the energy density of the Li/S battery has been improved to 500 Wh/kg and 600 Wh/L (discharge to 1.5V) in our lab. For another thing, by improving the electrolyte and separator, the Li/S coin cell could cycle 100 cycles (0.1 C) with capacity retention of 70% (still over 800mAh/g (S)) with 3.0 mg/cm²(S) cathode.

In this presentation, the development of Li/S battery in the energy storage department of DICP will be introduced, including materials design (cathode, electrolyte, and separator), preparation and soft package design. Battery performance with different carbon materials combined with different electrolyte and separators series will be summarized and discussed in detail.