High-performance lithium-selenium battery with Se/microporous carbon composite cathode and carbonate-based electrolyte

Selenium attracts increasing attention as cathode material for rechargeable lithium batteries due to its high conductivity and comparable volumetric capacity with sulfur. Microporous carbon spheres (MiPCS) are synthesized via a hydrothermal-annealing route followed by activation with KOH. The MiPCS are used as matrix for Se loading to form Se/MiPCS composite. Such composite delivers a high specific capacity close to the theoretical value of Se. In carbonate-based electrolyte, the capacity is as high as 733 mAh g−1 at a current density of 50 mA g−1, and 353 mAh g−1 at 5000 mA g−1. At 0.5 C, the capacity retains up to 515 mAh g-1 even after 100 cycles. Such outstanding electrochemical performance of the composite cathode in the carbonate electrolyte can be ascribed to the robust structure of MiPCS and to the “ solid-solid” electrode process.