Graphene oxide-protected three dimensional Se as a binder-free cathode for Li-Se battery

Lithium-selenium (Li-Se) battery is attractive because it has the potential to provide high energy density. However, the poor cyclic performance caused mainly by the shuttling of polyselenides and volumetric expansion of selenium limits its practical application. In this paper we report on a facile preparation of selenium on nickel foam by a galvanic replacement method, which can be directly used as a cathode for Li-Se battery without any binders or conductive additives. This material can deliver a capacity of 554 mAh g−1 (82% of theoretical capacity) and keep a capacity of 137 mAh g−1 after 100 cycles at a rate of 0.1C. A coating with graphene oxide as protection layer onto the Se surface can further enhance the electrode performance, achieving a capacity of 665 mAh g−1 (98.5% of theoretical capacity) in the first cycle and remains a capacity of 266 mAh g−1 after 100 cycles at a rate of 0.1C. The present work demonstrates significant progress in the development of high capacity cathode materials for lithium-selenium battery.