Preparation of thin solid electrolyte by hot-pressing and diamond wire slicing

Masashi Kotobuki; Houhua Lei; Yu Chen; Shufeng Song; Chaohe Xu; Ning Hu; Janina Molenda; Li Lu

doi:10.1039/c9ra00711c

Preparation of thin solid electrolyte by hot-pressing and diamond wire slicing

RSC Adv. 2019 Apr 15;9(21):11670-11675. doi: 10.1039/c9ra00711c. eCollection 2019 Apr 12.

Authors

Masashi Kotobuki^{1

2}, Houhua Lei³, Yu Chen^{2

4}, Shufeng Song⁵, Chaohe Xu⁵, Ning Hu⁵, Janina Molenda⁶, Li Lu^{1

2}

Affiliations

¹ Department of Mechanical Engineering, National University of Singapore 9 Engineering Drive 1 Singapore 117576 Singapore lluli@nus.edu.sg.
² National University of Singapore Suzhou Research Institute Dushu Lake Science and Education Innovation District Suzhou 215123 P. R. China.
³ Solid-Force Pte. Ltd. Dushu Lake Science and Education Innovation District Suzhou 215123 P. R. China.
⁴ School of Optoelectronic Science and Engineering, Collaborative Innovation Centre of Suzhou Nano Science and Technology, Soochow University Suzhou 215006 China.
⁵ College of Aerospace Engineering, Chongqing University Chongqing 400044 P. R. China.
⁶ AGH University of Science and Technology, Faculty of Energy and Fuels Mickiewicza 30 30-059 Krakow Poland.

Abstract

The thickness of a solid electrolyte influences the performance of all-solid-state batteries due to increased impedance with a thick electrolyte. Thin solid electrolytes are favourable to improve the performance of all-solid-state batteries due to the short Li ion diffusion path and small volume of the solid electrolytes. Therefore, the preparation of thin solid electrolyte is one of the key process techniques for development of all-solid-state batteries. In this study, thin Li_1.5Ge_1.5Al_0.5(PO₄)₃ solid electrolyte with a Na super ion conductor structure is prepared by diamond wire slicing. The Li_1.5Ge_1.5Al_0.5(PO₄)₃ solid electrolyte is prepared by melt-quenching followed by crystallization at 800 °C for 8 h, after which the crystallized Li_1.5Ge_1.5Al_0.5(PO₄)₃ rod is subjected to wire slicing. Thin Li_1.5Ge_1.5Al_0.5(PO₄)₃ with a thickness of 200 μm is obtained. The crystal structure and cross-sectional morphology are not affected by the slicing. The total Li conductivity of the thin Li_1.5Ge_1.5Al_0.5(PO₄)₃ and activation energy are 3.3 × 10^-4 S cm^-1 and 0.32 eV, respectively. The thickness and total conductivity are comparable to those of Li_1.5Ge_1.5Al_0.5(PO₄)₃ prepared by the tape-casting method which needs several steps to prepare Li_1.5Ge_1.5Al_0.5(PO₄)₃ tape-sheet and high temperature and a long sintering process. The ionic transference number of the thin Li_1.5Ge_1.5Al_0.5(PO₄)₃ is 0.999. The diamond wire slicing is a useful method to prepare thin solid electrolytes.