Hybrid oxide solid electrolyte of crystalline garnet and highly deformable glass for all-solid-state lithium-ion batteries

• Published in: Journal of power sources Vol. 539; p. 231596
• Main Authors: Nagata, Hiroshi, Akimoto, Junji
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.08.2022
• Subjects: all-Solid-state battery; Full battery cell; Hybrid oxide solid electrolyte; Full battery cell; all-Solid-state battery; Hybrid oxide solid electrolyte
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2022.231596

Oxide solid electrolytes (SEs) are promising materials for all-solid-state lithium-ion batteries because of their superior safety and stability. However, crystalline oxide SEs with relatively high ionic conductivity show low deformability and limited contact between SE particles, which hinders the formation of lithium-ion transport pathways. Meanwhile, highly deformable oxide glass SEs exhibit good contact between particles but low ionic conductivity. This study seeks to combine the advantages of both types of SEs in a hybrid oxide SE comprising a crystalline garnet-type oxide of Li6.5La3Zr1.5Ta0.5O12 (LLZT) and a deformable oxide glass 45Li2SO4–30Li2CO3–25LiBr. The controlled synthesis of LLZT via a flux method affords particles with suitable shape and size to allow the deformable SE to fill the interparticle spaces. The hybrid SE pellets prepared by cold pressing show a relative density of 96% and higher ionic conductivity than the original crystalline and glass SEs as a result of the good interparticle contact. Furthermore, oxide-type all-solid-state LiNi1/3Co1/3Mn1/3O2–Si and Li2S–Si full battery cells fabricated using the garnet–glass hybrid SE as a separator layer show relatively high area capacity and specific energy density compared with other oxide-type all-solid-state lithium-ion batteries. •Sharp shaped LLZT was preferable for filling deformable LSCB between particles.•The hybrid solid electrolyte showed high ionic conductivity and deformability.•An oxide-type all-solid-state full battery cell was fabricated by cold pressing.•NCM-Si and Li2S–Si oxide full cells showed high specific energy densities at 25 °C.