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Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g −1 at the current density of 6 A g −1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g −1 to 30 A g −1 . More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density. [ABSTRACT FROM AUTHOR]

Multi-component nanoporous platinum–ruthenium–copper–osmium–iridium (np-PtRuCuOsIr) electrocatalyst has been facilely fabricated by chemical dealloying of mechanically alloyed AlCuPtRuOsIr precursor. The np-PtRuCuOsIr catalyst exhibits a typical three-dimensional bi-continuous interpenetrating ligament/channel structure with a length scale of ∼2.5 nm. The np-PtRuCuOsIr catalyst reaches a higher level in the mass activity (857.5 mA mg Pt −1 ) and specific activity (3.0 mA cm −2 ) towards methanol oxidation compared to the commercial PtC catalyst (229.5 mA mg Pt −1 and 0.5 mA cm −2 respectively). Moreover, the CO stripping peak of np-PtRuCuOsIr is 0.54 V (vs. SCE), 130 mV negative shift in comparison with the commercial PtC (0.67 V vs. SCE). The half-wave potential of np-PtRuCuOsIr is 0.900 V vs. RHE, 36 mV positive compared with that of the commercial PtC (0.864 V vs. RHE). The np-PtRuCuOsIr catalyst also shows 1.8 and 3.8 times enhancement in the mass and specific activity towards oxygen reduction than the commercial PtC. Moreover, the np-PtRuCuOsIr alloy exhibits superior oxygen reduction activities even after 15 K cycles, indicating its excellent long-term stability. The present np-PtRuCuOsIr can act as a promising candidate for the electrocatalyst in direct methanol fuel cells (DMFCs). [ABSTRACT FROM AUTHOR]

Abstract The separator is a crucial part of lithium ion battery, such as preventing internal short-circuit and offering ion-conducting routes. However, conventional separators are usually based on polymer materials, which show the low thermal stability and poor electrolyte wettability, thus greatly restricting the electrochemical performance of lithium ion battery, especially for high-temperature safety. In this study, zeolitic imidazolate framework-67 (ZIF-67) was employed as separator via direct coating onto the surface of LiNi 0.5 Co 0.2 Mn 0.3 O 2 electrode through a facile blade-coating technique. Comparing with the conventionally used polypropylene (PP) separator, the new ZIF-67 based separator features superior electrolyte uptake (154%), higher ionic conductivity (0.00164 S cm−1) and thermal stability. Notably, at a high temperature of 55 °C, the cell with ZIF-67 based separator exhibits nearly 2 times higher capacity retention than the PP separator (ZIF-67: 61.20% vs PP: 35.09%). In view of its advantages, the ZIF-67 based separator shows significant potential in the design of safe lithium ion batteries. Graphical abstract Image 1 Highlights • ZIF-67 is demonstrated to use as the separator. • ZIF-67 based separator is directly coated on the LiNi 0.5 Co 0.2 Mn 0.3 O 2 electrode. • ZIF-67 based separator has higher thermal stability than polypropylene separator. [ABSTRACT FROM AUTHOR]