With continuous development of electronics, the requirements for power supply systems are increasing. Supercapacitors (SCs), which have high energy density and excellent power output performance, are ideal power supplies for new generation of miniaturized, intelligent and wearable electronic devices. Thus, developing SCs with fast charge-discharge speed and high stability is a key research topic in the field of energy storage. As the most important part of SCs, electrode materials are critical to its performance. Due to the excellent performances of high-ordered pore structure, large specific surface area, diverse morphologies and dimensions, and adjustable conductivity, conductive metal-organic frameworks (MOFs) materials have shown great potential as promising SCs electrode materials, and have attracted wide attention. This review introduces the structure, conductive mechanism and preparation methods of conductive MOFs following a short introduction of SCs, describes its design strategy as SCs electrode materials, reviews the research progress of conductive MOFs in the field of SCs, and prospects its future application.

Histidine-functionalized carbon dot/graphene aerogel (His-CDs/GA) were synthesized via the one-step hydrothermal method. The as-prepared His-CDs/GA exhibits unique three-dimensional porous structure, rich nitrogen and oxygen-containing functional groups, which facilitate the rapid diffusion of electrolyte ions and provide more active sites. When the mass ratio of GO and His-CDs is 2 : 1, the specific capacitance of His-CDs/GA-2 reaches 304 F·g ^-1 at a current density of 1 A·g ^-1, which increases 76.7% compared with that of GA (172 F·g ^{- 1}). With the current density increasing from 1 A·g ^-1 to 50 A·g ^-1, the specific capacitance retention of His-CDs/GA-2 achieves 71.4%. The specific capacitance of His-CDs/GA-2 still remains 93.5% over 30000 cycles at 10 A·g ^-1. In addition, a symmetrical supercapacitor assembled by His-CDs/GA possesses a high energy density of 10.14 Wh/kg at a power density of 250 W/kg, and good cyclic performance with 88.4% capacitance retention at 5 A·g ^-1 over 20000 cycles. The results show that His-CDs/GA is a promising electrode material for supercapacitors.

In order to improve the electrochemical performance, the phosphate ion doped MnFe₂O₄ (PMFO) was synthesized by a hydrothermal method combined with a subsequent phosphatization treatment. Both the specific surface area and electrical conductivity of electrode material are improved by the phosphate ion functionalization. Furthermore, the specific capacitance is 750 F/g at 1 A/g for PMFO, which is almost 1.7% higher than that of MFO. Besides, the cyclic stability of PMFO electrode is also improved. The asymmetric supercapacitors (ASCs) assembled by positive electrode PMFO and actived negative electrode carbon (AC) display an ultrahigh energy density of 168.8 Wh/kg at a power density of 2.7 kW/kg. The PMFO is demonstrated as a promising electrode material for supercapacitor applications.

Lithium metal anode, due to its highest theoretical specific capacity (3860 mAh·g ^-1) and lowest electrochemical potential (-3.04 V (vs SHE)), has become the first choice of the next generation of electrochemical energy storage devices. It is known as the “holy grail” of the battery industry. However, the disadvantage of lithium metal battery is particularly obvious: during the charge and discharge process, lithium metal battery is easy to deposit unevenly on the anode electrode, resulting in lithium dendrite which causes the continuous rupture and formation of solid electrolyte interface (SEI) film. The unstable SEI film, intensifying the formation of lithium dendrites and then piercing the separator, causes a decline for the battery cycle performance and the safety hazard. Therefore, it is particularly important to take corresponding measures to make lithium metal uniformly deposited on the anode. In this study, the uniform lithiophilic copper oxide nanosheet array formed on the surface of commercial copper mesh through oxidation of alkaline solvent and calcination of air. The 3D structure of copper mesh can effectively reduce the current density, and the lithiophilic nanosheet array can effectively reduce the overpotential of lithium deposition simultaneously. This lithiophilic 3D copper-based current collector makes lithium deposited uniformly and effectively, and inhibits the formation of lithium dendrites. In the half-cell test at a current density of 3 mA·cm ^-2 the battery circulated stably for 230 cycles with Coulombic efficiency remaining above 99%. The lithium iron phosphate (LFP) full battery with the as-prepared material as current collector worked stably for more than 300 cycles at 1C(0.17 mA·mg ^-1) and present a capacity retention of ~95%. This study provides a new design strategy of 3D current collector for stable lithium metal batteries.

Zinc-manganese (Zn/MnO₂) batteries with outstanding advantages of high operation safety, high environmental benignity and high cost performance, is suitable for the application of large-scale energy storage battery. However, the uncontrolled growth of zinc dendrites on the metal zinc anode during charge-discharge cycling causes serious problems such as quick capacity decrease and short circuit failure. In this study, the aqueous electrolyte was converted into a composite quasi-gel electrolyte by adding hydrophilic nano-silica (SiO₂) and sodium alginate (SA), which effectively inhibits the dendrite growth of the surface of the zinc negative electrode and the capacity degradation of the Zn-MnO₂ battery. Galvanostatic charge-discharge tests showed that the Zn/MnO₂ battery with composite gel electrolyte achieves a capacity retention of 78% after 1800 cycles, while the capacity of Zn/MnO₂ battery using ordinary electrolyte almost fails after 1000 cycles. The three-dimensional network structure of the gel electrolyte can improve the distribution uniformity of zinc ion in electrolyte, reduce the capacity decay rate and failure risk of the batteries.