Lithiophilic Nanoskin-Enabled Dendrite-Free Li Deposition in Pomegranate-like Carbon Microclusters

Abstract

The Pomegranate-like carbon microclusters (P-CMs), constructed from densely assembled hollow carbon spheres, provide interconnected internal voids that can accommodate Li and mitigate macroscopic volume changes. However, despite this advantageous architecture, Li deposition in P-CMs often remains surface-biased owing to insufficient interfacial lithiophilicity and non-uniform solid-electrolyte interphase formation. These interfacial limitations lead to localized Li nucleation, gradual Li accumulation on the outer surface, and eventual dendritic growth under prolonged cycling conditions.In this study, we applied a conformal polydopamine (PDA) nanoskin coating on the P-CM (the resulting sample is denoted as P-CM@PDA) to regulate its Li nucleation behavior and stabilize the interfacial chemistry. The PDA-derived catechol/amine functional groups provide abundant lithiophilic sites that lower the nucleation barrier and homogenize the Li + flux, while the hierarchical P-CM framework facilitates inward Li infusion through continuous ionic pathways. Consequently, P-CM@PDA achieves highly reversible Li plating/stripping, with a stable Coulombic efficiency of ~97% for 150 cycles at 3.0 mA h cm -2 , and maintains long-term symmetric cell cycling for more than 450 h at 2.0 mA cm -2 and 1.0 mA h cm -2 . When paired with a LiFePO4 cathode, the full cell delivers a high reversible discharge capacity of 141.8 mA h g -1 with > 99% capacity retention over 350 cycles and superior rate capability up to 10C rate. This study demonstrates that interfacial lithiophilicity enhancement, rather than structural redesign alone, is the key to enabling dense, dendrite-free Li storage in hierarchical carbon hosts, providing a promising pathway to high-energy lithium metal batteries.