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[en] Highlights: •Composite sulfur electrodes are prepared by high-temperature mechanical milling. •The composite exhibited a high discharge capacity of greater than 1200 mAh g−1. •Novel structure unit forms via a reaction between thio-LISICON and sulfur. •Liquid phase sulfur prevents severe decompositions of materials employed. -- Abstract: Composite sulfur electrodes are prepared by high-temperature mechanical milling (443 K) for use in all-solid-state lithium–sulfur batteries, and their structures and electrochemical properties are investigated. Composites comprising sulfur, acetylene black, and a Li3.25Ge0.25P0.75S4 solid electrolyte are fabricated by planetary ball milling using a temperature-controlled system. The composite electrode exhibits a high discharge capacity of greater than 1200 mAh g−1 and a good cycle capability. As a result of high-temperature milling, composites are formed, incorporating novel structural units from the reaction between sulfur and the solid electrolyte, along with their intrinsic characteristics. Hence, high-temperature milling demonstrates promise for the fabrication of a composite electrode exhibiting high, reversible electrochemical activities for use in an all-solid-state lithium–sulfur battery.
[en] In this study, we prepared a novel type of biofunctionalized poly(vinylidene fluoride) (PVDF) nanofibers. Cysteine, a natural amino acid, was grafted onto the surfaces of PVDF nanofibers, The −SH groups of cysteine were then oxidized to −SO3H. The formation of proton-conducting pathways was induced by the −SO3H and COOH groups of the oxidized cysteine chains on the surfaces of the biofunctionalized PVDF nanofibers. Composite membranes were fabricated by impregnating the biofunctionalized PVDF nanofibers with Nafion. Then, the effects of incorporating nanofibers grafted with different amounts of oxidized cysteine on the thermal stability, water uptake dimensional stability, proton conductivity, and single-cell performance of Nafion composite membranes were investigated. The properties of the composite membranes were superior to those of the Nafion membrane. Furthermore, Nafion/PVDF–Cys-30 exhibited the highest proton conductivity of 0.22 S cm−1 (80 °C), and the maximum power density of 108.42 mW cm−2 which was twice than the values of Nafion 117 membrane (51.2 mW cm−2) at 60 °C under 100% RH. The introduction of biofunctionalized nanofibers significantly improved cell performance, proton conductivity, dimensional stability, and methanol permeability of the membrane.
[en] A semi-solid state electrochromic device with deep eutectic solvent gel as the electrolyte, Ethyl-viologen as the electrochromic compound, and K4Fe(CN)6 as the electron donor was reported. Four kinds of silica were simply mixed with ethaline for preparing the gel electrolyte, and the hydrophilic ones were found to be capable of being used as the gelling agent. To enhance the electron transfer at the electrode/gel interface and keep the transparency of the electrode, tiny amount of Au was electrochemically deposited on the FTO electrode. The as-prepared electrochromic device shows a coloration time of ca. 60 s at −0.7 V with the coloration efficiency of 91 cm2/C, and a bleaching time of ca. 150 s at 0 V with the efficiency of 194 cm2/C. The reversible response of the electrochromic device up to 820 cycles with ΔTmax > 60% was also demonstrated.
[en] Many 2D graphene-based catalysts for electrooxidation of glucose involved the use of binders and toxic reducing agents in the preparation of the electrodes, which potentially causes the masking of original activity of the electrocatalysts. In this study, a green method was developed to prepare binder-free 3D graphene aerogel/nickel foam electrodes in which bimetallic Pd-Pt NP alloy with different at% ratios were loaded on 3D graphene aerogel. The influence of Pd/Pt ratio (at%: 1:2.9, 1:1.31, 1:1.03), glucose concentration (30 mM, 75 mM, 300 mM, 500 mM) and NaOH concentration (0.1 M, 1 M) on electrooxidation of glucose were investigated. The catalytic activity of the electrodes was enhanced with increasing the Pd/Pt ratio from 1:2.9 to 1:1.03, and changing the NaOH/glucose concentration from 75 mM glucose/0.1 M NaOH to 300 mM glucose/1 M NaOH. The Pd1Pt1.03/GA/NF electrode achieved a high current density of 388.59 A g−1 under the 300 mM glucose/1 M NaOH condition. The stability of the electrodes was also evaluated over 1000 cycles. This study demonstrated that the Pd1Pt1.03/GA/NF electrode could be used as an anodic electrode in glucose-based fuel cells.