Wet‐Chemical Tuning of Li3−xPS4 (0≤x≤0.3) Enabled by Dual Solvents for All‐Solid‐State Lithium‐Ion Batteries

• Published in: ChemSusChem 2020-01, Vol.13 (1), p.146-151
• Main Authors: Oh, Dae Yang, Ha, A. Reum, Lee, Ji Eun, Jung, Sung Hoo, Jeong, Goojin, Cho, Woosuk, Kim, Kyung Su, Jung, Yoon Seok
• Format: Article
• Language: English
• Subjects: Batteries; Chemical synthesis; Electrolytic cells; Flux density; liquid-phase synthesis; lithium; Lithium-ion batteries; Miscibility; Molten salt electrolytes; Organic chemistry; Photoelectrons; Rechargeable batteries; Solid electrolytes; solvent effects; Solvents; Tetrahydrofuran; Xylene
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201901850

All‐solid‐state lithium‐ion batteries (ASLBs) employing sulfide solid electrolytes are attractive next‐generation rechargeable batteries that could offer improved safety and energy density. Recently, wet syntheses or processes for sulfide solid electrolyte materials have opened opportunities to explore new materials and practical fabrication methods for ASLBs. A new wet‐chemical route for the synthesis of Li‐deficient Li3−xPS4 (0≤x≤0.3) has been developed, which is enabled by dual solvents. Owing to its miscibility with tetrahydrofuran and ability to dissolve elemental sulfur, o‐xylene as a cosolvent facilitates the wet‐chemical synthesis of Li3−xPS4. Li3−xPS4 (0≤x≤0.15) derived by using dual solvents shows Li+ conductivity of approximately 0.2 mS cm−1 at 30 °C, in contrast to 0.034 mS cm−1 for a sample obtained by using a conventional single solvent (tetrahydrofuran, x=0.15). The evolution of the structure for Li3−xPS4 is also investigated by complementary analysis using X‐ray diffraction, Raman, and X‐ray photoelectron spectroscopy measurements. LiCoO2/Li–In ASLBs employing Li2.85PS4 obtained by using dual solvents exhibit a reversible capacity of 130 mA h g−1 with good cycle retention at 30 °C, outperforming cells with Li2.85PS4 obtained by using a conventional single solvent. Get wet: A wet‐chemical route for the synthesis of Li‐deficient Li3−xPS4 (0≤x≤0.30) was enabled by using the dual solvents tetrahydrofuran and o‐xylene to develop all‐solid‐state batteries. Batteries employing Li2.85PS4 obtained by using dual solvents exhibit a reversible capacity of 130 mA h g−1 with good cycle retention at 30 °C.