Uniform lithium deposition enabled by a carbon nanotubes framework modified with nanosized ZIF-8 particles for dendrite-free lithium metal anode

Abstract

Lithium (Li) metal is considered as an exciting anode candidate for next-generation high-performance Li metal batteries because of its high theoretical capacity and lowest redox potential. Unfortunately, unavoidable challenges consisting of dendritic behavior and volume change obstruct its widely commercial application. Here, a three-dimensional (3D) oxidized carbon nanotubes framework modified with lithiophilic nano-ZIF-8 particles (CNTs@ZIF-8) has been fabricated by a simple solution method as the collector for uniform Li deposition. The polar groups from oxidized CNTs and ZIF-8 nanoparticles provide adhesion sites for Li nucleation. Meanwhile, the nano-ZIF-8 particles with large specific surface area enhance electrolyte absorption, attracting electrolyte to the CNTs surface. The composite structure with nanoscale surface modification can guide homogeneous Li plating and restrain Li dendrites growth. As a consequence, the symmetrical cell of CNTs@ZIF-8/Cu–Li reveals a stable cycle time (over 1500 h) with a hysteresis voltage (9 mV) at 1 mA cm⁻². The full cell assembled by LiFePO₄ (LFP) cathode and CNTs@ZIF-8/Cu–Li anode achieves outstanding rate and cycle performance which is superior to the CNTs/Cu–Li‖LFP, demonstrating that the CNTs@ZIF-8 is prospective for practical applications.