Stabilization of Superionic-Conducting High-Temperature Phase of Li(CB<sub>9</sub>H<sub>10</sub>) via Solid Solution Formation with Li<sub>2</sub>(B<sub>12</sub>H<sub>12</sub>)
oleh: Sangryun Kim, Kazuaki Kisu, Shin-ichi Orimo
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2021-03-01 |
Deskripsi
We report the stabilization of the high-temperature (high-<i>T</i>) phase of lithium carba-<i>closo</i>-decaborate<i>,</i> Li(CB<sub>9</sub>H<sub>10</sub>), via the formation of solid solutions in a Li(CB<sub>9</sub>H<sub>10</sub>)-Li<sub>2</sub>(B<sub>12</sub>H<sub>12</sub>) quasi-binary system. Li(CB<sub>9</sub>H<sub>10</sub>)-based solid solutions in which [CB<sub>9</sub>H<sub>10</sub>]<sup>−</sup> is replaced by [B<sub>12</sub>H<sub>12</sub>]<sup>2−</sup> were obtained at compositions with low <i>x</i> values in the (1−<i>x</i>)Li(CB<sub>9</sub>H<sub>10</sub>)−<i>x</i>Li<sub>2</sub>(B<sub>12</sub>H<sub>12</sub>) system. An increase in the extent of [B<sub>12</sub>H<sub>12</sub>]<sup>2−</sup> substitution promoted stabilization of the high-<i>T</i> phase of Li(CB<sub>9</sub>H<sub>10</sub>), resulting in an increase in the lithium-ion conductivity. Superionic conductivities of over 10<sup>−3</sup> S cm<sup>−1</sup> were achieved for the compounds with 0.2 ≤ <i>x</i> ≤ 0.4. In addition, a comparison of the Li(CB<sub>9</sub>H<sub>10</sub>)−Li<sub>2</sub>(B<sub>12</sub>H<sub>12</sub>) system and the Li(CB<sub>9</sub>H<sub>10</sub>)−Li(CB<sub>11</sub>H<sub>12</sub>) system suggests that the valence of the complex anions plays an important role in the ionic conduction. In battery tests, an all-solid-state Li–TiS<sub>2</sub> cell employing 0.6Li(CB<sub>9</sub>H<sub>10</sub>)−0.4Li<sub>2</sub>(B<sub>12</sub>H<sub>12</sub>) (<i>x</i> = 0.4) as a solid electrolyte presented reversible battery reactions during repeated discharge–charge cycles. The current study offers an insight into strategies to develop complex hydride solid electrolytes.