Multifunctional Integration in a Monolithic Biomass Carbon: A Triple‐Synergistic Host for Advanced Lithium–Sulfur Batteries

ABSTRACT

Lithium–sulfur (Li–S) batteries are promising for next‐generation high‐energy‐storage systems but are hindered by polysulfide shuttle, sluggish kinetics, and volume expansion. Conventional carbon hosts struggle to simultaneously anchor and convert polysulfides efficiently. Herein, we demonstrate a multifunctional biomass‐derived carbon host synthesized via controlled carbonization of bacterial cellulose (BC), endowed with a three‐dimensional (3D) interconnected nanofiber network, hierarchical micro‐/meso‐/macroporous architecture, and abundant intrinsic oxygen‐containing functional groups. A unique triple synergistic mechanism—integrating “physical confinement, chemical anchoring, and kinetic catalysis”—is systematically unraveled. Specifically, the 3D interconnected nanofiber network coupled with hierarchical porosity not only affords robust physical confinement to curb polysulfide diffusion but also constructs rapid ion/electron transport channels and buffers volume fluctuations during cycling. Benefiting from this integrated design, the sulfur cathode based on the BC‐derived carbon (CBC) host delivers an ultrahigh discharge specific capacity of 2246.5 mAh g ⁻¹ at 0.2C (surpassing sulfur’s theoretical capacity) and exhibits exceptional cycling stability with an ultralow average capacity decay rate of only 0.04% per cycle over 800 cycles at 3C. Even at high sulfur loadings (4.8 mg cm ⁻² ), the cathode maintains remarkable electrochemical performance. This work provides a high‐performance biomass‐derived host and offers insights for optimizing Li–S battery performance via rational carbon material design.