An Ultrahigh Capacity Graphite/Li2S Battery with Holey-Li2S Nanoarchitectures

Abstract

The pairing of high-capacity Li2S cathode (1166 mAh g(-1)) and lithium-free anode (LFA) provides an unparalleled potential in developing safe and energy-dense next-generation secondary batteries. However, the low utilization of the Li2S cathode and the lack of electrolytes compatible to both electrodes are impeding the development. Here, a novel graphite/Li2S battery system, which features a self-assembled, holey-Li2S nanoarchitecture and a stable solid electrolyte interface (SEI) on the graphite electrode, is reported. The holey structure on Li2S is beneficial in decomposing Li2S at the first charging process due to the enhanced Li ion extraction and transfer from the Li2S to the electrolyte. In addition, the concentrated dioxolane (DOL)-rich electrolyte designed lowers the irreversible capacity loss for SEI formation. By using the combined strategies, the graphite/holey-Li2S battery delivers an ultrahigh discharge capacity of 810 mAh g(-1) at 0.1 C (based on the mass of Li2S) and of 714 mAh g(-1) at 0.2 C. Moreover, it exhibits a reversible capacity of 300 mAh g(-1) after a record lifecycle of 600 cycles at 1 C. These results suggest the great potential of the designed LFA/holey-Li2S batteries for practical use.