Molecular-Level Dual-Ionophilic Passivation for High-Areal-Capacity Lithium Metal Anodes on Nanostructured Paper Electrodes

Abstract

Developing high-areal-capacity lithium metal anodes (LMAs) with exceptional reversibility, rapid charge-transfer kinetics, and long-term cycling stability remains a critical challenge for enabling next-generation high-energy-density lithium batteries. 2D electrodes suffer from poor rate performance and early lithium depletion at the electrode-electrolyte interface, while 3D architectures exhibit low Coulombic efficiency (CE) and excessive electrolyte consumption, compromising long-term stability. Herein, a nanostructured paper electrode (NPE) composed of oxygen-functionalized single-walled carbon nanotubes (Ox-SWCNTs) is introduced with a molecular-scale dual-ionophilic chitosan coating (C-NPE) to enhance LMA performance. The chitosan layer 1) reduces initial electrolyte decomposition to 1/25, 2) promotes an ultrathin, inorganic-rich solid-electrolyte-interface layer, and 3) increases active surface area and electrolyte uptake. At high areal capacity tests of 4.0 mA h cm(-)(2), the high CE of >99.0% is achieved, and the overpotential is reduced by half, sustaining stable cycling for over 350 cycles-a tenfold increase compared to the premature failure observed in NPEs at 35 cycles. Furthermore, when integrated into Li-S batteries, C-NPE-based LMAs exhibit markedly suppressed polysulfide shuttling, mitigating capacity decay and overpotential-induced voltage drop. This enables a high energy density of 2385 Wh kg(-)(1) and a power density of 3475 W kg(-)(1), with stable operation over 150 cycles.