Rechargeable lithium (Li) metal batteries have extremely high theoretical specific energy and energy density because Li metal anode has a significantly high theoretical capacity of 3860 mAh/g (10 times as large as that of graphite) and the lowest electrochemical potential at -3.040 V vs. standard hydrogen electrode. They are considered as the �holy grail� of energy storage systems.[1] However, the development and application of rechargeable Li-metal batteries has been hindered in the past four decades due to two major issues�the Li dendrite growth on Li anode during repeated charge/discharge processes leading to serious safety hazards and the low Coulombic efficiency since Li metal is strongly reactive to organic solvents and salt anions. During the past four decades, several approaches have been reported to improve the stability of Li metal anode, including using Li alloy, adding electrolyte additives, modifying Li surface, and so on. However, the improvement on Li anode as far is not satisfactory. In this work, we systematically investigated the effects of different electrolyte additives on Li deposition morphology and cycling efficiency. A novel self-healing electrostatic shield (SHES) mechanism has been proposed that fundamentally alters Li dendrite formation occurred in all traditional approaches.[2] With the help of the SHES additives added in the conventional Li-ion battery electrolytes, Li dendrite formation and growth has been significantly suppressed. By optimizing electrolyte solvents, Li salts and other additives, the Li Coulombic efficiency has also been greatly improved to >97% with dendrite-free morphology. The long-term cycling stability and dendrite-free Li anode and carbonaceous anodes have been achieved. Further development of this approach will lead to long-term, safe operation of rechargeable Li-metal batteries and Li-ion batteries. Details of the investigations will be reported and discussed in the presentation.

Dendrite-suppression electrolytes for rechargeable lithium batteries

247th National Meeting (2014)

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