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.