Room temperature rechargeable magnesium batteries with sulfur-containing composite cathodes prepared from elemental sulfur and bis(alkenyl) compound having a cyclic or linear ether unit

Room temperature rechargeable magnesium (Mg) batteries are constructed from Mg as a negative material, sulfur (S)-containing composite prepared from elemental sulfur and the bis(alkenyl) compound having a crown ether unit (BUMB18C6) or linear ether unit (UOEE) as a positive material and the simple electrolyte (0.7 mol dm(-3) Mg[N(SO2CF3)(2)](2)-triglyme (G3) solution). The reaction between molten S and the bis(alkenyl) compound (BUMB18C6 or UOEE) provides the sulfur-containing composite, S-BUMB18C6 or S-UOEE. Both of the sulfur-containing composites are electrochemically active in the Mg salt-based electrolyte, acetonitrile- or G3- Mg[N(SO2CF3)(2)](2) electrolyte. The first discharge capacity of the test cells with the sulfur-containing composite is 460 Ah kg(-1) (per the weight of sulfur in the composite) with the S-BUMB18C6 electrode and 495 Ah kg(-1) with the S-UOEE electrode. According to the continuous charge-discharge cycle tests (at 10th cycle), the discharge capacity of the test cell with the S-BUMB18C6 electrode (68.1 Ah kg(-1)) is higher than that with the S-UOEE electrode (0.18 Ah kg(-1)). The crown ether units in the S-BUMB18C6 composite may create ion-conducting paths in the cathode, prevent rise in the internal resistance of the cathode, and provide better cycle performance of the test cells with the S-BUMB18C6 composite electrode than that with the S-UOEE electrode. (C) 2015 Elsevier B.V. All rights reserved.