Supercapacitor electrodes based on metal‐organic compounds from the first transition metal series

Metal‐organic compounds, including molecular complexes and coordination polymers, have attracted much attention as electrode materials in supercapacitors owing to their large surface area, high porosity, tailorable pore size, controllable structure, good electrochemical reversibility, and abundant active sites. Among the variety of metal‐organic compounds exhibiting desired supercapacitor performances (high specific capacitance, long cycling life, high energy density, and power density), those with metals in the first transition metal series are the most studied due to their rich covalent states, light atom weight, environmental‐friendliness, non‐toxicity, and low cost. In this review, the recent reports on the metal‐organic compounds of the first transition metal series as electrode materials in supercapacitors are summarized and their electrode and device performances are discussed in terms of different metal elements and typical multidentate ligands. Moreover, the current challenges, design strategies, future opportunities and further research directions are also highlighted for metal‐organic compounds in the field of supercapacitors.