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(SO 2 CF 3) 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(SO 2 CF 3) 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 (68.1Ah kg-1) is higher than that with the S-UOEE electrode (0.18Ah 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.

The layered manganese dioxide (δ-type MnO2) film electrodeposited on carbon cloth (CC) functioned as a cathode in aqueous zinc-ion batteries. Battery performance was notably improved by doping MnO2 layers with cobalt and the CC surface with nitrogen. The δ-MnO2 interlayer accommodated Zn2+ ions in the as-deposited state and thus could act as an intercalation host during the discharging process. The Co-doped MnO2 film on the nitrogen-doped CC delivered a discharge capacity as high as 280 mA h g–1 at a specific current of 1.2 A g–1 for 600 charge/discharge cycles, while the discharge capacity did not exceed 30 mA h g–1 even at a specific current as high as 10.5 A g–1. These values are superior to those observed in the absence of doping, demonstrating the positive impact of Co- and N-doping into the MnO2 layers and the CC substrate on the cycling stability and rate capability.

p-Conjugated polymers are particularly interesting in the field of electro-optic materials because of their desirable properties such as electrical conductivity, nonlinear optics and electroluminescence. Coupling polymerizations of 2,3-dibromo-Nsubstituted maleimide (DBrRMI) (R¼benzyl, phenyl, cyclohexyl, n-hexyl and n-dodecyl) were carried out using palladium or nickel catalysts. The number-average molecular weights of poly(RMI-alt-Ph) obtained by Suzuki-Miyaura cross-coupling polymerizations of DBrRMI with benzene-1,4-boronic acid or 2,5-thiophene diboronic acid were 680-1270 by gel permeation chromatographic analyses. By contrast, Yamamoto coupling polymerizations of DBrRMI with diiodobenzene gave random poly(RMI-co-Ph) results. Poly(RMI-co-Ph)s exhibited a higher thermal stability than monomer and poly(RMI-alt-Ph). Copolymers showed strong photoluminescence from yellow to light blue colors in tetrahydrofuran.

The electrochemical behavior of magnesium (Mg) metal was investigated in tetrahydrofuran (THF)-based solutions containing magnesium bromide (MgBr 2 ) and/or magnesium ethoxide (Mg(OEt) 2 ). THF solutions containing a single solute, MgBr 2 or Mg(OEt) 2 , show no visible faradaic current based on Mg deposition and/or dissolution. However, the electrolyte system containing both solutes, MgBr 2 + Mg(OEt) 2 /THF, gives a reversible current response of Mg deposition and dissolution. The ionic structure of the electrolyte system containing the binary solute was examined by infrared (IR) spectroscopy and density functional theory (DFT) calculations. It was confirmed that MgBr 2 and Mg(OEt) 2 are coordinated (solvated) with THF molecules to form an EtO-Mg-Br•4THF complex. The DFT calculations also suggest the possible formation of -complexes for the MgBr 2 /Mg(OEt) 2 binary system in THF. The voltammetric responses at the Pt electrode indicate low overpotential and high coulombic efficiency for Mg deposition and dissolution in THF-based solutions containing suitable molar ratios of MgBr 2 and Mg(OEt) 2 . The constant-current charge-discharge cycling of Mg in MgBr 2 + Mg(OEt) 2 /THF electrolyte also shows low overpotential and good cyclability over 300 cycles.

Electrochemical deposition and dissolution of magnesium (Mg) has been examined in triethylene glycol dimethyl ether (triglyme, G3) dissolving magnesium bis(triflouromethanesulfonyl)amide, Mg(TFSA) 2 . The voltammetric current responses at platinum (Pt) electrode in the G3-based electrolytes revealed that the Mg deposition/dissolution process depends on the Mg species in the solution phase. The addition of alkoxides, Mg(OC n H 2n+1 ) 2 , was effective on the reversibility of the process in Mg(TFSA) 2 /G3. Higher anodic current corresponding to the electrochemical dissolution was observed in the electrolyte solution containing Mg(OC 2 H 5 ) 2 as the additive. The morphology of the Mg deposition at the Pt substrate also depended on the additive Mg-alkoxides. The resulting Mg(TFSA) 2 /G3 solutions containing Mg-alkoxides were found to be a possible electrolyte system for rechargeable Mg battery operating at ambient temperature.