Fabrication and electrochemical characteristics of NCM-based all-solid lithium batteries using nano-grade garnet Al-LLZO powder

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) Vol. 71; pp. 445 - 451
• Main Authors: Kim, Da Hye, Kim, Min Young, Yang, Seung Hoon, Ryu, Hye Min, Jung, Ha Young, Ban, Hee-Jung, Park, Sang-Jun, Lim, Jin Sub, Kim, Ho-Sung
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.03.2019; 한국공업화학회
• Subjects: All-solid lithium batteries; Composite electrolyte sheet; Cubic structure; Garnet-type nanopowder; Ionic conductivity; 화학공학; Garnet-type nanopowder; All-solid lithium batteries; Cubic structure; Ionic conductivity; Composite electrolyte sheet
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2018.12.001

[Display omitted] The composite electrolyte (CE) sheet was prepared by homogenously dispersing nano-grade Al-doped LLZO powder synthesized by employing the Couette–Taylor reactor in a PEO matrix. The all-solid lithium battery (ASLB) using the CE sheet was designed and manufactured with a cathode containing VGCF, which can be used to verify improved ASLB charge–discharge and lifetime characteristics. •Nanosized cubic phase Al-doped LLZO was formed using a Couette–Taylor reactor.•The Al-LLZO particles were observed as finely dispersed with a size of less than 100nm in the PEO matrix.•The resistance of the composite electrolyte sheet is almost due to the grain boundary resistance.•The cell was designed to confirmed the contribution to the lifetime and rate characteristics of VGCF on the cathode. Garnet-related Li6.25Al0.25La3Zr2O12 (Al-LLZO) powder was prepared by calcination the precursor synthesized a Couette–Taylor reactor. The powder comprised regular blocks (1–2μm) and consisted of fine particles (average particle size: D50=600nm, specific surface area: 2.42m2g−1) that adopted a highly crystalline nanoscale cubic structure (lattice parameter: a=13.07769Å; crystallite size: 41.4nm). A composite electrolyte (CE) sheet in which the Al-LLZO nanopowder was finely dispersed was prepared by casting a slurry comprising 70wt% Al-LLZO, polyethylene oxide (PEO), and lithium salt (LiClO4). The total ionic conductivity of the CE sheet was 7.59×10−6Scm−1 at 25°C and 1.93×10−3Scm−1 at 70°C, compared with 3.03×10−4Scm−1 at 25°C for the Al-LLZO pellet. Cyclic voltammetry showed that the electrochemical potential of the CE sheet was superior to that of PEO sheet. For application of the CE in all-solid lithium batteries (ASLBs), a composite NCM-based cathode composed of Al-LLZO, PEO, Super-P, and VGCF was also prepared. The discharge capacity of the cell was ∼122mAhg−1 at 0.1C & 70°C in voltages of 3.0–4.1V, and ∼80% of the initial capacity was maintained over 100 cycles with high rate characteristics.