In Situ Electrochemically Derived Amorphous-Li2S for High Performance Li2S/Graphite Full Cell

High-capacity Li2S cathode (1166 mAh g(-1)) is regarded as a promising candidate for the next-generation lithium ion batteries. However, its high potential barrier upon the initial activation process leads to a low utilization of Li2S. In this work, a Li2S/graphite full cell with the zero activation potential barrier is achieved through an in situ electrochemical conversion of Li2S8 catholyte into the amorphous Li2S. Theoretical calculations indicate that the zero activation potential for amorphous Li2S can be ascribed to its lower Li extraction energy than that of the crystalline Li2S. The constructed Li2S/graphite full cell delivers a high discharge capacity of 1006 mAh g(-1), indicating a high utilization of the amorphous Li2S as a cathode. Moreover, a long cycle life with 500 cycles for this Li2S/graphite full cell is realized. This in situ electrochemical conversion strategy designed here is inspired for developing high energy Li2S-based full cells in future.