In Situ Electrochemically Derived Amorphous-Li₂ S for High Performance Li₂ S/Graphite Full Cell

High-capacity Li₂ S 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 Li₂ S. In this work, a Li₂ S/graphite full cell with the zero activation potential barrier is achieved through an in situ electrochemical conversion of Li₂ S₈ catholyte into the amorphous Li₂ S. Theoretical calculations indicate that the zero activation potential for amorphous Li₂ S can be ascribed to its lower Li extraction energy than that of the crystalline Li₂ S. The constructed Li₂ S/graphite full cell delivers a high discharge capacity of 1006 mAh g^-1 , indicating a high utilization of the amorphous Li₂ S as a cathode. Moreover, a long cycle life with 500 cycles for this Li₂ S/graphite full cell is realized. This in situ electrochemical conversion strategy designed here is inspired for developing high energy Li₂ S-based full cells in future.