Efficient Ni_2Co_4P_3 Nanowires Catalysts Enhance Ultrahigh- Loading Lithium-Sulfur Conversion in a Micro reactor-Like Battery

摘要

High-loading lithium-sulfur (Li-S) batteries suffer from poor electrochemical properties. Electrocatalysts can accelerate polysulfides conversion and suppress their migration to improve battery cyclability. However, catalysts for Li-S batteries usually lack a rational design. A d-band tuning strategy is reported by alloying cobalt to metal sites of Ni2P to enhance the interaction between polysulfides and catalysts. A molecular or atomic level analysis reveals that Ni2Co4P3 is able to weaken the S-S bonds and lower the activation energy of polysulfides conversion, which is confirmed with temperature-dependent experiments. Ni2Co4P3 nanowires are further fabricated on a porous nickel scaffold to unfold the catalytic activity by its large surface area. Using a simple ion-selective filtration shell, a microreactor-like S cathode (MLSC) is constructed to realize ultrahigh S loading (25 mg cm(-2)). As such, a microreactor design integrates reaction and separation in one cell and can effectively address the polysulfide issues, the MLSC cell demonstrates excellent properties of cyclability and high capacity (1223 mAh g(-1) at 0.1 C). More importantly, the catalyst's designs and microreactor strategies provide new approaches for addressing the complicated issues of Li-S batteries.