Copper sulfide with flower-like (f-CuS) and carambola-like (c-CuS) morphologies was successfully synthesized by a facile one-step solvothermal route with different surfactants. When employed as cathode catalysts for lithium-oxygen batteries (LOBs), f-CuS outperforms c-CuS in terms of oxygen electrochemistry, judging from the faster kinetics and the higher reversibility of oxygen reduction/oxidation reactions, as well as the better LOB performance. Moreover, an abnormal high-potential discharge plateau was observed in the discharge profile of the LOB. To understand the different performances of f-CuS and c-CuS and the abnormal high-potential plateau, theoretical calculations were conducted, based on which a mechanism was proposed and verified with experiments. On the whole, CuS can work as a multifunctional catalyst for promoting LOB performance, which means that the dissolved CuS in LiTFSI/TEGDME electrolyte can serve as a liquid catalyst by the redox couples of Cu(TFSI)2/Cu(TFSI)2-/Cu(TFSI)22-, in addition to the function as a traditional solid catalyst in the cathode.

Multifunctional Catalyst CuS for Nonaqueous Rechargeable Lithium-Oxygen Batteries.

New qualitative colour reaction for the identification of copper(I) compounds and complexes.

The sodium salt of 1-allyl-2-tetrazoline-5-thione (NaATT-5) is proposed as a new reagent for the detection of IO3−, I−, and Bi(III) ions. An aqueous solution of NaATT-5 reduces IO3− in acid medium to free iodine (formed via iodide) which is detected by reaction with starch. S2O32− is the only interfering species. I− and NO2− interfere only when both are present together. NaATT-5 also reacts with bismuth to form a canary yellow precipitate of [BiL2]+ X− (where X=a univalent anion other than I−; L=ATT-5). When the yellow precipitate is treated with iodide, X− is replaced by I− to form a complex [BiL2]+I−, which is orange in colour. This reaction provides the basis for the detection of bismuth as well as of I−. In the test for bismuth, Cu(II), Fe(III), S2O32−, IO3−, IO4−, and large quantities of NO2− interfere. The last four anions also interfere in the test for iodide. A method for the preparation of NaATT-5 is also reported.

G. S. Johar

Papers

New qualitative colour reaction for the identification of copper(I) compounds and complexes.

1-Allyl-2-tetrazoline-5-thione as a reagent in inorganic qualitative analysis. Micro detection of iodate, iodide, and bismuth(III).