Realizing High Utilization of High-Mass-Loading Sulfur Cathode via Electrode Nanopore Regulation.

Abstract

One main challenge of realizing high-energy-density lithium-sulfur batteries is low active materials utilization, excessive use of inert components, high electrolyte intake, and mechanical instability of high-mass-loading sulfur cathodes. Herein, chunky sulfur/graphene particle electrodes were designed, where active sulfur was confined in vertically aligned nanochannels (width ∼12 nm) of chunky graphene-based particles (∼70 μm) with N, O-containing groups. The short charge transport distance and low tortuosity enabled high utilization of active materials for high-mass-loading chunky sulfur/graphene particle electrodes. The intermediate polysulfide trapping effect by capillary effect and heteroatoms-containing groups, and a mechanically robust graphene framework, helped to realize stable electrode cycling. The as-designed electrode showed high areal capacity (10.9 mAh cm^-2) and high sulfur utilization (72.4%) under the rigorous conditions of low electrolyte/active material ratio (∼2.5 μL mg^-1) and high sulfur loading (9.0 mg cm^-2), realizing high energy densities (520 Wh kg^-1, 1635 Wh L^-1).