Li-Ion Conductivity Enhancement of LiBH4· x NH3 with In Situ Formed Li2O Nanoparticles

Wanying Zhao; Ruixue Zhang; Hongjiao Li; Yunsheng Zhang; Yao Wang; Chaoling Wu; Yigang Yan; Yungui Chen

doi:10.1021/acsami.1c06164

Li-Ion Conductivity Enhancement of LiBH₄· x NH₃ with In Situ Formed Li₂O Nanoparticles

ACS Appl Mater Interfaces. 2021 Jul 14;13(27):31635-31641. doi: 10.1021/acsami.1c06164. Epub 2021 Jun 28.

Authors

Wanying Zhao¹, Ruixue Zhang², Hongjiao Li³, Yunsheng Zhang¹, Yao Wang^{2

4}, Chaoling Wu^{1

4}, Yigang Yan^{2

4}, Yungui Chen^{2

4}

Affiliations

¹ College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China.
² Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610207, China.
³ College of Chemical Engineering, Sichuan University, Chengdu 610207, China.
⁴ Engineering Research Center of Alternative Energy Materials and Devices, Ministry of Education, Chengdu 610207, China.

PMID: 34181395
DOI: 10.1021/acsami.1c06164

Abstract

Interfacial engineering is an efficient approach to improve the ionic conductivity of solid-state electrolytes. In the present study, we report the enhancement of in situ formed nanocrystalline Li₂O on the thermal stability and electrochemical properties of amide lithium borohydride, LiBH₄·xNH₃ (x = 0.67-0.8). LiBH₄·xNH₃-Li₂O composites with different amounts of Li₂O are prepared by a one-step synthesis process by ball milling the mixture of LiBH₄, LiNH₂, and LiOH in molar ratios of 1:n:n (n = 1, 2, 3, 4). Owing to the strong interfacial effect with nanocrystalline Li₂O, LiBH₄·xNH₃ is converted to the amorphous state in the presence of 78 wt % Li₂O at n = 4. Consequently, the ionic conductivity of LiBH₄·xNH₃ at 20 °C is improved by orders of magnitude up to 5.4 × 10^-4 S cm^-1, the NH₃ desorption temperature is increased by more than 20 °C, and the electrochemical window is widened from 0.5 to 3.8 V.

Keywords: amide lithium borohydride; interfacial effect; ionic conductor; nanosized oxide; solid-state battery.