Shape‐Assisted 2D MOF/Graphene Derived Hybrids as Exceptional Lithium‐Ion Battery Electrodes

Abstract

Abstract Herein, a novel polymer‐templated strategy is described to obtain 2D nickel‐based MOF nanosheets using Ni(OH) 2 , squaric acid, and polyvinylpyrrolidone (PVP), where PVP has a dual role as a structure‐directing agent, as well as preventing agglomeration of the MOF nanosheets. Furthermore, a scalable method is developed to transform the 2D MOF sheets to Ni 7 S 6 /graphene nanosheet (GNS) heterobilayers by in situ sulfidation using thiourea as a sulfur source. The Ni 7 S 6 /GNS composite shows an excellent reversible capacity of 1010 mAh g −1 at 0.12 A g −1 with a Coulombic efficiency of 98% capacity retention. The electrochemical performance of the Ni 7 S 6 /GNS composite is superior not only to nickel sulfide/graphene‐based composites but also to other metal disulfide–based composite electrodes. Moreover, the Ni 7 S 6 /GNS anode exhibits excellent cycle stability (≈95% capacity retention after 2000 cycles). This outstanding electrochemical performance can be attributed to the synergistic effects of Ni 7 S 6 and GNS, where GNS serves as a conducting matrix to support Ni 7 S 6 nanosheets while Ni 7 S 6 prevents restacking of GNS. This work opens up new opportunities in the design of novel functional heterostructures by hybridizing 2D MOF nanosheets with other 2D nanomaterials for electrochemical energy storage/conversion applications.