Monoclinic ZIF-8 Nanosheet-Derived 2D Carbon Nanosheets as Sulfur Immobilizer for High-Performance Lithium Sulfur Batteries

2D hierarchically porous carbon (2D-HPC) nanosheets with unique advantages are highly desired as host materials for lithium sulfur (Li–S) batteries and other energy storage devices. Herein, we propose a self-template and organic solvent-free approach to synthesize nanosheets of monoclinic ZIF-8 at room temperature from which 2D-HPC nanosheets (ZIF-8 nanosheets carbon denoted as ZIF-8-NS-C) are derived to be an efficient sulfur immobilizer for Li–S batteries for the first time. The anisotropic nanosheets are believed to relate to the symmetry of the monoclinic structure. The 2D ZIF-8-NS-C nanosheets with embedded hierarchical pores construct an effective conductive network through “plane-to-plane” modes to endow superior electron transfer and fast electrochemical kinetics. Moreover, the nitrogen-rich feature of ZIF-8-NS-C can increase the affinity/interaction of carbon host with lithium polysulfides, favoring the cyclic performance. The sulfur/ZIF-8-NS-C (S/ZIF-8-NS-C) cathode shows a superior rate capability with high capacities of 1226 mA h g–1 at 0.2 C and 785 mA h g–1 at 2 C, and a sustainable cycling stability with a capacity attenuation of 0.12% per cycle at 0.5 C for 300 cycles. The approach proposed here pioneers the controllable design of MOF-based structures to inspire the exploration of more variable MOF-derived porous materials for energy storage applications.