Chinese Academy of Sciences makes progress in research on all-solid lithium-sulfur batteries

Although all-solid lithium sulphide can solve the problems faced by traditional lithium-sulfur batteries, it brings new challenges, such as solid-solid interface problems and battery capacity attenuation caused by effects such as stress/strain, which affects all-solid lithium. The key to the cycle life of sulfur batteries. Recently, a team led by Yao Xiayin, a researcher in the Solid State Lithium Battery Team of the Institute of Materials and Engineering, Chinese Academy of Sciences, and the University of Maryland, designed a new solid-state lithium-sulfur battery with a sulfur-positive structure, by depositing ultra-thin on reduced graphene oxide. The (~2nm) amorphous nano-sulfur layer maintains the high electron conductivity of the composite, and then uniformly reduces the reduced graphene oxide/sulfur composite in the super-lithium ion conductor Li10GeP2S12 matrix composite, thereby achieving high ionic conductivity and Low stress/strain. The above-mentioned reduced graphene oxide/sulfur composite material-Li10GeP2S12-acetylene black mixture is used as the positive electrode layer, Li10GeP2S12/modified Li3PS4 double-layer electrolyte is used as the solid electrolyte layer, and lithium metal is the negative electrode assembled all-solid lithium-sulfur battery, and its charge and discharge curve and the tradition Lithium-sulfur batteries are completely different, only a pair of charging and discharging platforms, significantly inhibiting the production of polysulfides.

At 60 °C, the initial discharge capacity of 0.05C was 1629mAh/g, and the first coulombic efficiency reached 90%. At the same time, it showed excellent rate performance. It was charged and discharged at different rates of 0.1C, 1.0C and 2.0C, and played 1384.5. Reversible capacity of 903.2 and 502.6mAh/g; 1.0C large-rate long-term cyclic charge and discharge, can still maintain the reversible capacity of 830mAh/g after 750 cycles, and the single-cycle capacity decay rate of the battery is only 0.015%, which is more traditional than Lithium-sulfur batteries have significantly improved cycle performance.

Related work is published in Advanced Energy Materials (2017, doi: 10.1002/aenm.201602923).

The above research work was supported by the Chinese Academy of Sciences Nano Pilot Project (XDA09010201), the National Natural Science Foundation, and the Chinese Academy of Sciences Youth Promotion Association.

Figure: Schematic diagram of the structure of an all-solid lithium-sulfur battery and battery performance