Thiospinels show interesting catalytic and energy storage applications, however, the cationic disorder can have major influence on the energy generation and/or energy storage applications. In this study, the effect of stoichiometric variation of metals in a thiospinel i.e. Ni_xCo_3−xS₄, is examined on energy generation and storage properties. Nickel- or cobalt-rich Ni_xCo_3−xS₄ nanosheets were prepared by the hot injection method using single molecular precursors. The nanosheets were characterized by p-XRD, TEM, HR-TEM, EDX and XPS techniques. Nickel-rich and cobalt-rich nanosheets were tested for oxygen and hydrogen evolution reactions and for supercapacitance performance. It was observed that the nickel-rich Ni_xCo_3−xS₄ nanosheets have superior energy storage and energy generation properties.