Hosting Li0 in an activated lithiophilic polymer matrix with electrodeposition regulating spaces for stable lithium metal anodes

Abstract

The cyclability of rechargeable high-energy-density lithium (Li) metal batteries (LMBs) is seriously limited by the Li dendrite induced volume variation and safety hazards. Herein, a hierarchical host composed of a robust polyethylene terephthalate (PET) matrix as the primary backbone and carbon nanotube (CNT) sponges as the pore fillers is fabricated as an advanced model structure for highly reversible Li storage. Compared with the conventional three-dimensional hosts in which the Li deposition confinement is not controlled in the void pores, extremely smooth Li deposition can be accommodated in the CNT sponges of the confined spaces, leading to a step towards better Li protection. Furthermore, a niobium (Nb)-based coating is revealed as a rational process to not only enable uniform solid electrolyte interphase with fast Li+ migration ability of the PET-CNT-Nb host, but also to activate the abundant polar lithiophilic segments (CO or -O-) of the PET matrix for guided Li nucleation. Based on the multifunctional PET-CNT-Nb host, stable cycling of LMBs with a practical capacity of ∼2.5 mAh cm−2 can be achieved over 400 cycles, demonstrating the rationality of the investigated host structuration rule for great Li protection ability.