High utilization lithium metal anode constructed by allocatable MXene foam container.

Electrode/electrolyte contact failure caused by thick dead Li and SEI layer is principally responsible for the low utilization of lithium metal anode. The key to opening this lock is designing a host with fast mass transfer to promote uniform deposition of lithium to reduce the repeated SEI growth and dead Li production. Herein, an allocatable container constructed with porous MXene (Ti 3 C 2 T x) and carbon nanofibers is proposed for constraining Li deposition behavior. Multiphysics finite elemental analysis and SEM confirm the fast mass transfer ability and good deposition behavior of MXene foam. The benefit of this allocatable container is further confirmed by the symmetric cells, with lifetime of 1400 h at 1 mA cm−2, 1 mAh cm−2 and 200 h at 5 mA cm−2, 5 mAh cm−2. Morphology after cycle displays that the composite anode makes the utmost utilization of lithium metal. Moreover, full-cell armed with this composite Li anode and LiFePO 4 cathode exhibits galvanostatic charge/discharge performance with 510 cycles at 2C and 100 cycles at 4C (1C = 170 mA g−1). This work sheds light on reasonable Li metal container design, highlights the importance of high Li utilization and puts the practical usage of Li metal battery one more step forward. [Display omitted] • MXene foam was constructed by porous MXene and carbon nanofibers. • Porous structure of MXene foam improves mass transfer ability. • MXene foam has good deposition behavior and suitable thickness of Li. • The composite anode achieved a high utilization of lithium metal. [ABSTRACT FROM AUTHOR]