Lithium aluminum hydride Li₃AlH₆: new insight into the anode material for liquid-state lithium-ion batteries

Metal hydrides have been demonstrated as one of the promising high-capacity anode materials for Li-ion batteries. Herein, we report the electrochemical properties and lithium storage mechanism of a Li-rich complex metal hydride (Li₃AlH₆). Li₃AlH₆ exhibits a lithiation capacity of ∼1729 mAh/g with a plateau potential of ∼0.33 V vs. Li⁺/Li at the first discharge cycle. Experimental results demonstrate that Li₃AlH₆ is converted into LiH and LiAl in the initial electrochemical lithiation process. In addition, Li₃AlH₆ also possesses a good cycling stability that 71 % of the second discharge capacity is retained after 20 cycles. More importantly, the cycling performance of Li₃AlH₆ can be improved to 100 cycles via adjusting electrolyte composition. This study provides a new approach for developing the lithium storage properties of anode materials for Li-ion batteries.