MOF (Metal-Organic Framework) based materials have attracted recent interest as-anode materials for Alkali-ion batteries. However, the insertion reaction that dictates the alkali ion storage in the MOFs being a conversion reaction depicts the drastic drop in cycling and rate stabilities. Herein we report a low-temperature twinning of a representative Ni-MOF with rGO (reduced graphene oxide) by low-temperature processing and through an intermediate physical mixing method to enhance the electrochemical anodic performance of the parent pristine Ni-based MOF that is Ni-MOF. The uniqueness of this process is that low-temperature processing (300 °C) ensures that the identity of MOF is maintained but generates intimate contacts between the Ni-MOF and thermally reduced GO (Graphene Oxide). The Ni-MOF@rGO composite so achieved has delivered a considerably enhanced rate and cycling stability with a capacity of 385 mAhg À 1 (100 mAg À 1 ) which stays consistent till 400 charge-discharge cycles against the pristine MOF which degrades to 272 mAg À 1 in just 250 cycles. The rate enhancements at higher currents are also substantial with the Ni-MOF@rGO composite depicting the capacity of 205 mAhg À 1 at 1 Ag À 1 as against the capacity of 113 mAhg À 1 for pristine Ni-MOF. The Ni-MOF@ rGO also depicts a considerably enhanced performance compared to carbonized (600 °C and 800 °C) control samples.

A schematic illustration depicting the electrochemical water splitting by Co9S8–NiCo2S4/N-rGO heterocatalyst.