Deeply Cyclable and Ultrahigh-Rate Lithium Metal Anodes Enabled by Coaxial Nanochamber Heterojunction on Carbon Nanofibers.

Lithium metal anodes (LMAs) are the most promising candidates for high-energy-density batteries due to the high theoretical specific capacity and lowest potential. However, the practical application of LMAs is hampered by the short lifespan and unsatisfactory lithium utilization (<50%). An oxide-oxide heterojunction enhanced with nanochamber structure design is proposed to improve lithium utilization and cycling performance of LMA under ultrahigh rates. Typically, a MnO2 -ZnO heterojunction provides high binding energy for strong absorption of Li-ions and intimately bonded interfaces for fast transfer of electrons. Under the guidance of the smooth Li-ion migration and rapid electron flow, the Li metal can be restricted as thin layers within submicro scale in nanochambers with constrain boundary and stress dissipation, inhibiting the local agglomeration and blocking. Thus, the lithiophilic active sites can be effectively exposed to the Li-ions within submicro scale, improving the reversible conversion for high lithium utilization during long-term cycling. As such, the Li@MnZnO/CNF electrode achieves a high lithium utilization of 70% at a record-high current density of 50 mA cm-2 with areal capacity of 10 mAh cm-2 . This work offers an avenue to improve lithium utilization for long-lifespan LMAs working under high current densities and capacities.