Long Cycle Life Lithium Metal Batteries Enabled with Upright Lithium Anode

The lithium metal anode is the holy grail of the battery field due to its lowest reduction potential and high specific capacity; however, its application is hindered by severe safety hazards and inferior cyclic stability due to dendrites and unstable solid electrolyte interphase (SEI). Aiming at these problems, a coiled Li anode with a unique upright structure is proposed. The upright structure endows coiled Li anode with abundant inner reaction interface/space/mass for lithium deposit/storage/transport, which can induce the inner growth of Li dendrites and SEI. The Li+ transport/deposit behavior and mechanism of coiled Li anode are clarified via in situ observation and numerical simulation. Benefiting from the small volume expansion and sufficient Li+ transport, the coiled Li anodes combined with Li4Ti5O12 cathodes achieve a long life of over 2000 cycles at 5C with a reversible capacity of 129 mAh g(-1) and 100% Coulombic efficiency.