Search

Zn–iodine (I2) battery, as a promising energy storage device, especially under high I2 loading, is harassed by the shuttle effect of the soluble polyiodide intermediates. Herein, the bifunctional role of 2D carbon nanosponge with rich P‐dopant (4.2 at%) and large specific surface area (1966 m2 g−1) in anchoring I2/Ix− (x = 1, 3 or 5) and catalyzing their mutual conversion is reported. Both experiment and computational results reveal the transfer of electrons from the P‐doped site to iodine species, showing strong interfacial interaction. When being used as a host, it possesses high specific capture capacity for I2 (3.34 giodine g−1 or 1.6 mgiodine m−2) and Ix− (6.12 gtriiodide g−1 or 3.1 mgtriiodide m−2), which thus effectively suppresses the shuttle effect, supported by in situ UV–vis and Raman spectra. In addition to the strong interfacial interaction that favors iodine conversion, the P‐doped sites can also catalyze the conversion of I5− to I2, which is the rate‐determining step. Consequently, Zn–I2 batteries under a high I2 content (70 wt%) deliver high specific capacity (220.3 mAh g−1), superior Coulombic efficiency (>99%), and low self‐discharge rate; moreover, they can also operate steadily at 2 A g−1 with ignorable capacity decay for 10 000 cycles. [ABSTRACT FROM AUTHOR]

Water splitting, to produce hydrogen and oxygen, has long been considered to be a desirable option for the storage of electrical energy. The catalysts for oxygen evolution reactions (OER) are very important in this process. Herein, we have synthesized Co3V2O8 nanoparticles by a simple and cost-effective technique, which have low crystallinity and large specific surface area (122.8 m2 g−1). Because of the low crystallinity, large specific surface area and suitable pore size, Co3V2O8 nanoparticles yielded an electrocatalytic OER current density of up to 429.7 mA cm−2 at 2.05 V vs. RHE and low OER over potentials of 359 mV (at 10 mA cm−2) and 497 mV (at 100 mA cm−2). In addition, the OER stability of the Co3V2O8 catalyst was very excellent, and the current density at 2.05 V was reduced by just 7.3% after galvanostatic OER measurement at 10 mA cm−2 for 3 h. This work demonstrates that binary metal oxides Co3V2O8 is a highly active and stable oxygen evolution electrocatalyst that can potentially replace expensive noble metal-based anode catalysts for electrochemical water splitting to generate hydrogen fuels. [ABSTRACT FROM AUTHOR]