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Metal-organic frames (MOFs) are regarded as excellent candidates for supercapacitors that have attracted much attention because of their diversity, adjustability and porosity. However, both poor structural stability in aqueous alkaline electrolytes and the low electrical conductivity of MOF materials constrain their practical implementation in supercapacitors. In this study, bimetallic CoNi-MOF were synthesized to enhance the electrical conductivity and electrochemical activity of nickel-based MOF, as well as the electrochemical performance of the CoNi-MOF in multiple alkaline electrolytes was investigated. The CoNi-MOF/active carbon device, as-fabricated with a 1 M KOH electrolyte, possesses a high energy density of 35 W h kgâˆ'1 with a power density of 1450 W kgâˆ'1, exhibiting outstanding cycling stability of 95% over 10,000 cycles. The design of MOF-based electrode materials and the optimization selection of electrolytes pave the way for constructing high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) with numerous potential pseudocapacitive sites are quite appealing to supercapacitors with high specific and areal capacitances. However, MOFs suffer from a low conductivity nature, resulting in a mediocre electrochemical performance. Herein, we propose a template-growth strategy of MOF to enhance both specific and areal capacitances of MOF as the electrode material for supercapacitor. As the loading mass of MOF increases from 2 to 5 mg, the specific capacitance also increases from 937 to 2387 Fg−1 (431 to 1098 Cg−1) and areal capacitance 1.87 to 11.94 Fcm−2 (0.86 to 5.49 Ccm−1). Accordingly, a hybrid MOF//AC supercapacitor can deliver a maximum energy density of 67 Wh kg−1 and a maximum power density of 6000 W kg−1. These results point to a way to fabricate MOF electrode of supercapacitor with high specific and areal capacitance, which leads them to a more practical future. [ABSTRACT FROM AUTHOR]

Although there are numerous virtues for lithium sulfur batteries, the notorious shuttle effect and insulated nature are impeding their practical application. To address these issues, here we report the design and synthesis of polypyrrole coated sulfur and cobalt co-doped carbon nanocages (PSCC). It demonstrates that both the performance and stability of the PSCC assisted Li-S batteries are improved. The hollow structure of PSCC bypassed the structural collapse effectively caused by volume expansion of sulfur during the reaction and physically suppressed shuttle effect of the intermediate product polysulfide lithium (LiPSs). Also, LiPSs was also trapped to inhibit the shuttle effect due to the strong adsorption of LiPSs via PSCC. In addition, PSCC can also provide an outstanding electronic conductivity, which will facilitate the next-step reaction of the absorbed LiPSs and enhance electrochemical reaction kinetics. Thus, the excellent rate performance was obtained with high specific discharge capacities of 1300 mAh g−1 at 0.1 C and 1000 mAh g−1 at 0.5 C. Such packaged high-performance positions our design for the ideal electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]