To improve the cyclability of a LiMn 2 O 4 /graphite lithium ion battery at elevated temperature, a carbonatebased electrolyte using prop-1-ene-1,3-sultone (PES) as additive was developed. The cycling performance of the LiMn 2 O 4 /graphite cell, based on the developed electrolyte at 60 C, was evaluated by a constant current charge/discharge test, with comparison of the electrolyte using vinylene carbonate (VC) as additive. It was found that the cell based on the developed electrolyte exhibits better cyclability and exhibits better dimensional stability at elevated temperatures. The capacity retention is 91% and the swell value in thickness is 3.4% for the cell with PES after 150 cycles at 60 C, while the respective values were 68% and 36.4% for the cell without additive, and 82% and 9.1% for the cell with VC. The results obtained from scanning electron spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermal gravimetric analysis, and molecular energy level calculations show that PES favors the formation of a stable solid electrolyte interphase, not only on the anode but also on the cathode of the LiMn 2 O 4 / graphite battery, effectively preventing electrolyte decomposition.

Na based all-solid-state batteries are a promising technology for large-scale energy storage applications owing to good safety properties and low cost. High performance solid electrolyte materials with high room temperature ionic conductivity, good electrochemical stability and facile synthesis are highly desired for the commercialization of this technology. In this work, we report the synthesis and characterization of a novel fast Na-ion conductor, cubic Na3SbSe4, with an excellent ionic conductivity of 0.85 mS cm–1 at room temperature, and a group of S doped variants. Na3SbSe4 exhibits good compatibility with metallic Na and good stability in a wide voltage range. The application of this compound as solid electrolyte is demonstrated in all-solid-state Na-ion cells cycled at room temperature.

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