Spear-shaped Mn/Ni bimetallic hydroxide derived from metal-organic frameworks as electrode materials for aqueous and all-solid-state hybrid supercapacitors

MOF-derived hydroxides provide a promising platform for high performance supercapacitors as electrode materials. Herein, a novel manganese-nickel double hydroxide (MnNiDH) composite with special morphology has been successfully prepared by alkalizing the precursor Mn/Ni-MOF-74. Obtaining electrode material inherits the spear-shaped morphology of the precursor well and possesses a smaller particle size by potassium hydroxide treatment. The smaller particle size and rich microporous structure can shorten the ion or proton transport path, thereby improve its electrochemical activity and utilization. Benefiting from these specific properties, the resultant MnNiDH composite demonstrates a high specific capacitance of 2498 F g(-1) at a current density of 1A g(-1). The assembled aqueous device exhibits high energy density of 58.53Wh kg(-1), meanwhile the all-solid-state device also displays energy density of 30.63 Wh kg(-1) based on the outstanding voltage window of 0 similar to 2.1 V. These results suggest that as-synthesized MnNiDH hold great potential for practical applications in the energy storage field.