Using lithium bis(oxalato)borate for a fluoride shuttle battery in organic solvents allowed a successful fluoride shuttle-based redox reaction.

No abstract

As described in this paper, phosphonic-acid-containing double-decker-shaped polyhedral silsesquioxane (PHOS-DDSQ) was synthesized and the proton conductivity of the PHOS-DDSQ cast film was studied under humid and non-humid conditions. To synthesize PHOS-DDSQ, double-deckershaped polyhedral silsesquioxane (DDSQ) was initially reacted with di(ethylene glycol) (DEG) vinyl ether using hydrosilylation reaction to attach four DEG units to one DDSQ (4DEG-DDSQ). Subsequently, a phosphate esterification of hydroxyl groups in 4DEG-DDSQ was carried out using POCl 3 . NMR, XPS, and MALDI-TOF MS spectra and titration measurements revealed that the phosphate esterification connected two DEG units to form a crown-ether-like structure. This structure prevents hydrolysis of the phosphate ester bond. PHOS-DDSQ showed high thermal stability, with decomposition temperature exceeding 220 C, because of its inorganic DDSQ core. A uniform film of PHOS-DDSQ can be fabricated by drop casting. The cast film showed high proton conductivity (0.12 S cm À1 ) under humid conditions, which is comparable to that of a NafionÒ membrane. Moreover, the cast film offered good proton conductivity under non-humid conditions (3.6 Â 10 À4 S cm À1 at 170 C). The conductivity and thermal stability indicate that PHOS-DDSQ is a good candidate for use as a proton-conductive membrane in hydrated type fuel cells as well as fuel cells operated at intermediate temperatures (100-200 C) under non-humid conditions.

Bismuth fluoride (BiF3) is a promising positive electrode material for fluoride shuttle batteries (FSBs) owing to its high theoretical specific capacity (302 mA h g -1 ). However, it exhibits low practical capacity. The methods for preparing the electrode are known to have significant effects on battery performance. The mixture between BiF3 and carbon, BiF3/C, prepared by high energy ball milling method has been already approved in lithium ion batteries. With this method, a significant improvement over the discharge and charge capacities of the BiF3/C electrode has been achieved. In this work, for the first time, BiF3/C electrode has been used for FSB. Using BiF3/C electrode significantly increased the discharge and charge capacities. To confirm the progress of the discharge and charge reactions of BiF3/C electrode, the crystal structure of active materials and oxidation state of Bi for the BiF3/C electrode during discharge and charging has been investigated by X-ray diffraction and X-ray absorption fine structure. The results reveal that, with higher capacity values, discharge and charge reactions related to BiF3/C have been realized.

A double-decker-silsesquioxane (DDSQ) based transition-metal-complex showed efficient energy-conversion owing to the assembling ability of the complexes in the DDSQ nano-building blocks.