Breaking Down the Crystallinity: The Path for Advanced Lithium Batteries

DOI: 10.1002/aenm.201501933 one of the most promising lithium-based batteries, the Li-S batteries are appealing as both the sulfur cathode and the lithiummetal anode offer an order of magnitude higher charge-storage capacity compared to the currently used insertion-compound electrodes. [ 16,17 ] In addition, sulfur is abundant and environmentally benign while lithium metal offers a desirable low negative electrochemical potential. Unfortunately, the lithium-metal anode suffers from nonuniform metal redeposition and unstable surface chemistry in organic electrolytes, which lead to a continuous breakdown and reformation of the solid electrolyte interphase (SEI) layer during cycling. [ 18 ] To stabilize the lithium-metal anode, various electrolyte systems that target the reduction of the amount of free solvent molecules causing unwanted side reactions have been proposed. [ 19–21 ] Stable high-rate performance with lithium-metal anode has been reported by employing electrolytes with high lithium-salt concentrations, but the practical application of these electrolyte systems in Li-S batteries has not been verifi ed. [ 22 ] Alternatively, the concept of artifi cial SEI layers has been proposed, e.g., isolation of the lithium anode by hollow carbon nanosphere or lithiated graphite fi lms. [ 23,24 ] Albeit increased cycling effi ciency, the stability of the artifi cial SEIs in Li-S cells and their large-scale production remain a challenge for industrial applications. [ 25 ]