Elaborately converting hierarchical NiCo–LDH to rod–like LDH–decorated MOF as interlayer for high–performance lithium–sulfur battery

Abstract

Inserting an interlayer between sulfur cathode and separator is an effective strategy to suppress polysulfide shuttling for lithium–sulfur (Li–S) battery. Herein, we report a convenient solvothermal conversion of hierarchical NiCo–layered double hydroxide (NiCo–LDH) into the corresponding LDH–decorated metal–organic framework (NiCo–MOF/LDH) nanorods by tuning the ligand concentration. The Li–S batteries with the interlayer of NiCo–MOF/LDH nanorods exhibit a high specific capacity of 950 mAh g−1 after 200 cycles at 1 C with an ultralow capacity decay rate of 0.033% per cycle as well as excellent rate capability, much superior to the counterparts with pure NiCo–MOF or NiCo–LDH interlayers or blank case. The excellent Li–S battery performance results from the strong chemical adsorption of NiCo–LDH to polysulfides and the superior electrocatalysis of NiCo–MOF to sulfur conversion chemistry, as confirmed by the combined experimental and theoretical simulations, which synergistically suppress the shuttle and polarization effects to improve the rate capability and cycling stability of Li–S batteries. This study provides an elaborate in situ conversion approach for hybridizing LDH and MOF with respective strong adsorption and electrocatalysis function to polysulfides, which leads to the advanced interlayer material of NiCo–MOF/LDH for high–performance Li–S battery with potential applications.