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(100 − x)(0.75Li2S·0.25P2S5)·xLiBH4 (0 ≤ x (mol%) ≤ 33) glass electrolytes were prepared from 75Li2S·25P2S5 (mol%) glass and LiBH4 crystal by a mechanical milling technique. The effects of the addition of LiBH4 on the structures and properties of the glass electrolytes were examined. The DSC curves of the prepared glasses with LiBH4 did not have the endothermic peak attributable to the phase transition of LiBH4 crystal. The Raman spectra of the glasses indicated that the glasses included PS4 3− and BH4 − ions. The conductivities of the glasses increased with increasing the LiBH4 content. The glass at the composition of x = 33 showed the highest lithium-ion conductivity of 1.6 × 10−3 S cm−1 at room temperature. The glass had a wide electrochemical window up to 5 V vs. Li+/Li. An all-solid-state Li/TiS2 cell using the glass as an electrolyte successfully operated as a secondary battery at 25 °C. [ABSTRACT FROM AUTHOR]

Abstract: Electrode–electrolyte composite materials were prepared by coating a highly conductive Li2S–P2S5 solid electrolyte onto LiCoO2 electrode particles using pulsed laser deposition (PLD). Cross-sections of the composite electrode layers of the all-solid-state cells were observed using a transmission electron microscope to investigate the packing morphology of the LiCoO2 particles and the distribution of solid electrolyte in the composite electrode. All-solid-state cells based on a composite electrode composed entirely of solid-electrolyte-coated LiCoO2 were fabricated, and their performance was investigated. The coating amounts of Li2S–P2S5 solid electrolytes on LiCoO2 particles and the conductivity of the coating material were controlled to increase the capacity of the resulting all-solid-state cells. All-solid-state cells using LiCoO2 with thick solid electrolyte coatings, grown over 120min, had a capacity of 65mAhg−1, without any addition of Li2S–P2S5 solid electrolyte particles to the composite electrode. The capacity of the all-solid-state cell increased further after increasing the conductivity of the Li2S–P2S5 solid electrolyte coating by heat treatment at 200°C. Furthermore, an all-solid-state cell based on a composite electrode using both a solid electrolyte coating and added solid electrolyte particles was fabricated, and the capacity of the resulting all-solid-state cell increased to 95mAhg−1. [Copyright &y& Elsevier]

Abstract: All-solid-state lithium secondary batteries using LiCoO2 active materials coated with Li2SiO3 and SiO2 oxide films and Li2S–P2S5 solid electrolytes were fabricated and their electrochemical performance was investigated. The electrochemical performace of the all-solid-state cells at a high voltage region was highly improved by using oxide-coated LiCoO2. The oxide coatings are effective in suppressing the formation of an interfacial resistance between LiCoO2 and the solid electrolyte at a high cutoff voltage of 4.6V (vs. Li). As a result, charge–discharge capacities and cycle performance at the cutoff voltage were improved. The cell with Li2SiO3-coated LiCoO2 showed a large initial discharge capacity of 130mAhg−1 and a good capacity retention of 110mAhg−1 after 50th cycles at the cutoff voltage of 4.6V (vs. Li). [Copyright &y& Elsevier]