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

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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.

An oligo/poly(methyl(2‐(tris(2‐H methoxyethoxy)silyl)ethyl)siloxane)), 390EO, and 2550EO, were synthesized. Dilute electrolyte solutions of 390EO and 2550EO were prepared using LiTFSI, LiFSI, and LiPF6. The influence of the length of the siloxane polymer chain, salt type, and Si‐tripodand centers at the side chain on ionic conductivity, tLi+, and physical properties were examined. Both electrolyte systems showed high values of tLi+ (0.35 for 2550EO/LiTFSI and 0.64 for 390EO/LiTFSI). Alternatively 390EO/LiPF6 and 2550EO/LiPF6 displayed high tLi+ values of 0.61 and 0.44, respectively, while 390EO/LiFSI displayed the smallest tLi+ (0.25). To clarify the role played by the Li+ environment in Li+ transport, the solvation states of electrolytes were examined. It was observed that anion solvation can be achieved using siloxane‐based solvent in all systems. Walden plot analysis demonstrates that ionic diffusion was not controlled by either macroviscosity/microviscosity in the siloxane‐based polymer electrolytes. Ions instead move along a relatively smooth ion‐pathway without complete full segmental reorientation in 2550EO as a result of decoupling and high ion solvation behavior. Conversely, in 390EO, ions might move to available sites by a jumping after decoupling with low ion solvation behavior. Consequently, a high t Li+ was achieved, and the oxidative stability of the salt was ensured.

To exploit the excellent safety as well as the thermal and electrochemical properties of siloxane-based liquid electrolytes, 2,2,4,4-tetramethyl-3,8,11,14,17-pentaoxa-2,4-disilaoctadecane was used as an electrolyte for the first time in a fluoride shuttle battery system.

No abstract