Balancing Transport‐Accessible Catalytic Interfaces and Li ⁺ Transport via Porosity Engineering for High‐Performance Li–S Batteries

ABSTRACT The sluggish conversion of lithium polysulfides (LiPSs) to Li ₂ S represents the rate‐determining step in lithium sulfur (Li–S) batteries. While catalytic sulfur hosts have been extensively investigated to accelerate the sulfur redox reaction (SRR), the effect of host architecture in governing Li ⁺ transport and SRR kinetics remains insufficiently understood. Here, 2D Co ₃ S ₄ with tunable architectures is employed as a model electrocatalyst to elucidate this structural influence. Combined experimental analyses and COMSOL simulations reveal an intrinsic trade‐off between catalytic material packing and transport‐accessible interfacial activity: increasing structural compactness in dense Co ₃ S ₄ concentrates catalytic material but simultaneously increases Li ⁺ transport resistance and concentration polarization, whereas porous frameworks facilitate Li ⁺ migration and suppress concentration gradients. An optimized porous Co ₃ S ₄ architecture balances accessible catalytic interfaces with efficient Li ⁺ transport, thereby accelerating SRR kinetics and regulating Li ₂ S deposition. As a result, Li–S cells incorporating this optimized Co ₃ S ₄ host deliver long‐term cycling stability, retaining 657 mAh g ⁻¹ at 0.2 C with a low‐capacity decay of 0.051% per cycle over 1000 cycles. These findings establish porosity engineering as a critical design principle for catalytic sulfur hosts in high‐performance Li–S batteries.