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Stable Interface Formation between TiS2 and LiBH4 in Bulk-Type All-Solid-State Lithium Batteries

Published

Author(s)

Atsushi Unemoto, Tamio Ikeshoji, Syun Yasaku, Motoaki Matsuo, Vitalie Stavila, Terrence J. Udovic, Shin-Ichi Orimo

Abstract

In this study, we assembled a bulk-type all-solid-state batter comprised of a TiS2 positive electrode, LiBH4 electrolyte, and Li negative electrode. Our battery retained high capacity over 300 discharge-charge cycles when operated at 393 K and 0.2 C. The 2nd discharge capacity was as high as 205 mAh b-1, corresponding to a TiS2 utilization ratio of 85%. The 300th discharge capacity remained as high as 180 mAh g-1 with nearly 100 % coulombic efficiency from the 2nd cycle. Negligible impact of the exposure of LiBH4 to atmospheric-pressure oxygen on battery cycle life was also confirmed. To investigate the origin of the cycle durability for this bulk-type all-solid-state TiS2/Li battery, electrochemical measurements, powder X-ray diffraction measurements, thermogravimetry coupled with gas composition analysis, and first-principles molecular dynamics simulations were carried out. Chemical and/or during the initial charge. During this oxidation reaction of LiBH4 with hydrogen (H2) release just beneath the TiS2 surface, a third phase, likely including Li2B12H12, precipitated at the LiBH4-TiSd2^ interface. Li2B12H12 has a lithium ionic conductivity of log(ς/S cm01)= -4.4, charge transfer reactivity with Li electrodes, and superior oxidative stability to LiBH4, and thereby can act as a stable interface that enables numerous discharge-charge cycles. Our results strongly suggest that the creation of such a stable inter-facial layer is due to the propensity of forming highly stable, hydrogen-deficient complex hydrides such as Li2B12H12, which are thermodynamically available in the ternary Li-B-H system.
Citation
Chemistry of Materials
Volume
27
Issue
15

Keywords

battery, ionic conductivity, lithium, lithium battery, lithium borohydride, solid electrolyte, solid-state battery, titanium disulfide, rechargeable battery

Citation

Unemoto, A. , Ikeshoji, T. , Yasaku, S. , Matsuo, M. , Stavila, V. , Udovic, T. and Orimo, S. (2015), Stable Interface Formation between TiS<sub>2</sub> and LiBH<sub>4</sub> in Bulk-Type All-Solid-State Lithium Batteries, Chemistry of Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918679 (Accessed April 20, 2024)
Created August 10, 2015, Updated October 12, 2021