High-Performance All-Solid-State Lithium–Sulfur Batteries Enabled by Amorphous Sulfur-Coated Reduced Graphene Oxide Cathodes

5 years ago

High-Performance All-Solid-State Lithium–Sulfur Batteries Enabled by Amorphous Sulfur-Coated Reduced Graphene Oxide Cathodes

Chunsheng Wang, Qiang Zhang, Xiaoxiong Xu, Hongli Wan, Fudong Han, Jean Pierre Mwizerwa, Ning Huang, Xiayin Yao

Safety and the polysulfide shuttle reaction are two major challenges for liquid electrolyte lithium–sulfur (Li–S) batteries. Although use of solid-state electrolytes can overcome these two challenges, it also brings new challenges by increasing the interface resistance and stress/strain. In this work, the interface resistance and stress/strain of sulfur cathodes are significantly reduced by conformal coating ≈2 nm sulfur (S) onto reduced graphene oxide (rGO). An Li–S full cell consisting of an rGO@S-Li10GeP2S12-acetylene black (AB) composite cathode is evaluated. At 60 °C, the all-solid-state Li–S cell demonstrates a similar electrochemical performance as in liquid organic electrolyte, with high rate capacities of 1525.6, 1384.5, 1336.3, 903.2, 502.6, and 204.7 mA h g−1 at 0.05, 0.1, 0.5, 1.0, 2.0, and 5.0 C, respectively. It can maintain a high and reversible capacity of 830 mA h g−1 at 1.0 C for 750 cycles. The uniform distribution of the rGO@S nanocomposite in the Li10GeP2S12-AB matrix generates uniform volume changes during lithiation/delithiation, significantly reducing the stress/strain, thus extending the cycle life. Minimization of the stress/strain of solid cells is the key for a long cycle life of all-solid-state Li–S batteries. A ≈2 nm amorphous sulfur-coated reduced graphene oxide composite is employed in all-solid-state lithium–sulfur batteries. The composite can significantly reduce the interface resistance and stress/strain of sulfur cathodes, thus leading to an ultrastable all-solid-state lithium–sulfur battery with excellent rate capability and cycling stability, showing reversible capacities of 830 mA h g−1 at 1.0 C for 750 cycles.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/aenm.201602923