3D-Printed Catalytic Microlattice Cathode for High-Loading and Lean-Electrolyte Lithium-Sulfur Batteries

Abstract

As one of the important candidate systems in the “post-lithium-ion batteries” era, lithium-sulfur (Li-S) batteries have developed rapidly in recent decades. However, the practical energy density achievable for Li-S batteries still has a certain gap to meet the demands of practical applications, which is mainly attributed to excessive electrolyte usage. In this paper, this key issue has been effectively alleviated through a two-pronged approach that combines electrocatalysis and electrode structure design. On the one hand, VC0.75 was in situ grown on the surface of graphene (VC0.75/G), forming a heterostructure catalyst between the two. This catalyst can strongly anchor the dissolved long-chain Li2Sn molecules and catalyze the rate-limiting step of the sulfur redox reaction, namely the deposition/decomposition of Li2S. On the other hand, the microlattice electrode fabricated via 3D printing features a dual-scale pore structure, consisting of through-hole channels perpendicular to the electrode plane and abundant micro-nano pores inside the printed filaments. This well-designed architecture significantly facilitates electrolyte infiltration and mass transport within the thick electrode. Consequently, this VC0.75/G microlattice cell can achieve discharge capacities of 882.8 mAh g–1 at 0.05 C and 1206.4 mAh g–1 at 0.02 C under the conditions of an ultra-high sulfur areal loading of ∼31 mg cm–2 and a lean electrolyte of 5 μL mg−1, corresponding to remarkable areal capacities of 27.8 and 37.4 mAh cm–2. This integrated approach highlights the synergistic role of architectural engineering and catalytic activation in addressing the key challenges of sluggish reaction kinetics and low sulfur utilization rate for high sulfur loading and lean electrolyte Li-S batteries.