ChemInform Abstract: Ultra Fast Elemental Synthesis of High Yield Copper Chevrel Phase with High Electrochemical Performance (original) (raw)
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A fundamental study to understand the mechanism of the novel electrolysis of chalcocite (Cu2S) in a cuprous chloride (CuCl) – potassium chloride (KCl) molten salt was conducted to develop an efficient and environmentally friendly copper (Cu) metal production process. To measure the estimated decomposition voltage of the Cu2S feedstock and supporting electrolyte, the redox potentials of CuCl and Cu2S in the CuCl – KCl molten salt were measured using cyclic voltammetry (CV) measurements. The redox potential of CuCl was analyzed by considering impurities, phases, and molecular structures. The estimated decomposition voltages of Cu2S and CuCl in the CuCl – KCl molten salt were 0.31 and 0.75 V at 473 K, respectively. In addition, the electrolysis of Cu2S was conducted using a Cu cathode and carbon (C) anode in the CuCl – KCl molten salt under an applied current of 0.043 A at 473 K for 24 h. After electrolysis was completed, Cu metal with a purity of 99.99 % and elemental S were obtained ...
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Rechargeable magnesium sulfur (Mg/S) batteries suffer from fast capacity fading due to difficulty of reoxidation of MgS and the polysulfide shuttle. Other works have reported that use of Cu current collectors or CuS at the cathode improves cycleability. Here we investigate Cu nanoparticles grown on carbon nanofibers (Cu@CNF) as an additive for the Mg/S battery cathode to test the effects of Cu metal on capacity and rate performance at controlled Cu loading. The Mg/S battery with Cu additives can run at 1 C with a capacity of 452 mAh/g after 100 cycles. It was confirmed via X-ray photoelectron spectroscopy that Cu2S forms during cathode formation and contributes to the high initial capacity, but then converts back to metallic Cu. Upon extending cycling, the Cu additives promote the formation of smaller, more dispersed discharge product particles, thereby enhancing reversibility. Finally, it is found that the loading of S and Cu at the cathode must be low to achieve substantial and su...