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Li2S is a promising cathode candidate for all-solid-state batteries (ASSBs) because of its high theoretical capacity and availability for coupling with a Li-free anode or an anode-less electrode. However, ionically insulating Li2S leads to excess conductive additives, low sulfur utilization and sluggish kinetics, which hinders the implementation of high energy density potential by ASSBs. Improving the intrinsic conductivity of Li2S is the key to solve this issue. In this study, PI3-doped Li2S cathodes were fabricated and the relationship between lithium vacancies and ionic conductivities was examined quantitatively by the time-of-flight (TOF) neutron diffraction. By cation–anion dual doping, the ionic conductivities of Li2S–PI3 materials were improved to 10−4 S cm−1, which is desirable for the cathode without solid electrolytes added. Upon simply mixing with carbon, the Li2S–PI3–C cathode shows a high overall cathode capacity of 541 mA h g−1 with a high S utilization of 82% at 0.05C and a capacity of 207 mA h g−1 at 1C at room temperature, realizing high energy density with good rate performance. [ABSTRACT FROM AUTHOR]

Lithium-ion conducting glass-ceramic electrolyte in the composition 75Li2S·5P2S3 ·20P2S5 (mol%) was prepared by heat treatment of an amorphous precursor. The amorphous precursor was obtained by a high-energy ball-milling process. The glass ceramic showed high ion conductivity 2.0×10−3 Scm−1 at room temperature. Raman scattering measurements suggested that the glass ceramic essentially composed of thio-phosphate anions, PS4 3− and P2S6 4−, as structural units. A laboratory-scale all-solid-state battery was also assembled by use of the glass ceramic as solid electrolytes and LiNi1/3Mn1/3Co1/3O2 powders as positive electrode materials. The all-solid-state battery showed good charge–discharge cycle performance at room temperature under a constant current density of 0.1 mAcm−2. [ABSTRACT FROM AUTHOR]

Abstract: LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 powders were prepared by a sol–gel method associated with ultra-sonication, and the obtained LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 was investigated as positive electrode materials for all-solid-state batteries with sulfide-based solid electrolytes. All-solid-state lithium batteries were assembled with the obtained LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 powders and with amorphous Li3PS4 as solid electrolytes. The charge–discharge cycle performance of the all-solid-state cells was improved by the LiAlO2-coating on LiNi1/3Mn1/3Co1/3O2 powders. The LiAlO2 coating was effective in suppressing an increasing of the interfacial resistance between the LiNi1/3Mn1/3Co1/3O2 electrode material and the sulfide based solid electrolyte, Li3PS4, during charge–discharge cycling. The battery with the 1.0mol% LiAlO2-coated LiNi1/3Mn1/3Co1/3O2 showed an initial discharge capacity of 134 mAhg−1 and the battery retained the capacity more than 124 mAhg −1 even after 400 charge–discharge cycles at a current density of 11 mAg −1 at room temperature. [Copyright &y& Elsevier]

Abstract: All-solid-state lithium batteries were fabricated by use of LiNi1/3Mn1/3Co1/3O2 powders coated with ZrO2 as positive electrode materials and amorphous Li3PS4 as solid electrolytes. The ZrO2-coated powders were prepared by a sol–gel method associated with ultrasonic irradiation. The charge–discharge cycle performance of the all-solid-state cells was improved by use of the ZrO2-coated LiNi1/3Mn1/3Co1/3O2 powders. The ZrO2 coating was effective in suppressing an increasing of the interfacial resistance between the LiNi1/3Mn1/3Co1/3O2 electrode material and the sulfide based solid electrolyte, a-Li3PS4, during charge–discharge cycling. The battery with the ZrO2-coated LiNi1/3Mn1/3Co1/3O2 showed an initial discharge capacity of 115mAhg−1 and good capacity retention even after 50cycles at a current density of 0.1mAcm−2 at room temperature. [Copyright &y& Elsevier]

Abstract: Lithium-ion conducting solid electrolytes in the composition (100-x)Li3PS4·xLiAlS2 (mol%) were prepared by the use of a high-energy ball-milling process at room temperature. Amorphous samples were obtained in the composition range of x=0 to x=13.1. In the composition of x≥18.2, a crystalline Al2S3 phase remained in the samples which were ball-milled for 35h. The lithium ion conductivity at 298K of the obtained amorphous samples was increased with an increase in the compositional parameter x and showed the maximum at the compositional parameter x=13.1 (86.9Li3PS4·13.1LiAlS2: σ298K =6.0×10−4Scm−1 at 298K). [Copyright &y& Elsevier]

Abstract: Preparation of lithium ion conducting solid electrolytes in the composition 75Li2S·xP2S3·(25−x)P2S5 (mol%) was attempted by use of a high-energy ball-milling process at room temperature. Amorphous samples were obtained in the composition range of x=0 to x=5. In the samples with x ≥ 8.3, a crystalline Li2S phase was remained after the ball milling for 50 h. The lithium ion conductivity at 298 K of the amorphous samples was increased with an increase in x, and the amorphous sample with x=5 showed the highest lithium ion conductivity of 6.2×10−4 S·cm−1 at 298 K among the obtained samples. A laboratory-scale all-solid-state lithium battery using the amorphous sample with x=5 showed good discharge–charge performance at room temperature. [Copyright &y& Elsevier]

Abstract: Li4.4GexSi1−x alloys were prepared by use of a high-energy ball-milling process. The Li4.4GexSi1−x alloys formed a solid solution over the whole composition range of 0≤x≤1. Those alloys were isomorphic with an Li15Ge4 crystalline phase that had a D86 structure belonging to a space group I4¯3d. The lattice constants of the alloys were increased with an increase in the compositional parameter x. The Li4.4GexSi1−x alloys were investigated as negative electrode materials for all-solid-state lithium batteries with an inorganic solid electrolyte a-60Li2S·40SiS2 (mol%). Among the obtained alloys, the Li4.4Ge0.67Si0.33 alloy showed the largest specific capacity of 190 mA h g−1 and good charge–discharge reversibility. [Copyright &y& Elsevier]

Amorphous fine powders in the system AgI–Ag2PO3.5 were obtained over a wide composition range of 20–70 mol% AgI by a high-energy ball-milling process. While an amorphous sample was not obtained of the composition 80AgI · 20Ag2PO3.5 (mol%) by the ball-milling process, the amorphous sample-forming region by the high-energy ball-milling process was very similar to the glass-forming region by a conventional melt-quenching method. The 60AgI · 40Ag2PO3.5 (mol%) composition, at which an amorphous sample was obtained by ball milling to 48 h, was the most easily amorphous-forming composition in the system AgI–Ag2PO3.5. Ball-milled samples showed high ion conductivities at room temperature. The σ298 of the 60AgI·40Ag2PO3.5 sample changed with the ball-milling time. The σ298 steeply increased with an increase in the milling time and showed a maximum of 7.3×10−1 Sm−1 at around 20 h. It was noted that the maximum conductivity was higher than the conductivity of the melt-quenched glass with the same chemical composition. The σ298 of the samples ball-milled for longer than 30 h decreased with an increase in the milling time, and had a similar value as that of a melt-quenched glass. [Copyright &y& Elsevier]

An all-solid-state lithium battery was assembled with sulfur as positive electrode materials and with an inorganic solid electrolyte a-60Li2S⋅40SiS2 (mol %). The all-solid-state lithium battery showed successive reversibility with large specific capacity. The specific capacity calculated on the base of the mass of sulfur was more than 1000 mA⋅h⋅g-1. [ABSTRACT FROM AUTHOR]

Amorphous solid electrolytes in the system Li[sub2]S-P[sub2]S[sub3] were obtained in a narrow composition range at around 66.7 mol % Li[sub2]S content by a high-energy ball-milling process. The 66.7Li[sub2]S.33.3P[sub2]S[sub3] (mol %) sample showed the highest ion conductivity of 1.1 x 10[sup-4] S.cm[sup-1] at room temperature among the obtained samples. Cyclic voltammetry revealed that the sample had a wide electrochemical window of about 5 V. [ABSTRACT FROM AUTHOR]