A Low-cost and Air-Stable Rechargeable Aluminum-Ion Battery.

Rechargeable aluminum-ion batteries (AIBs) are promising for large-scale energy storage due to the abundant reserve, low cost, and high capacity of Al anode. However, the development of AIBs is currently hindered by the usage of AlCl3 /1-ethyl-3-methylimidazolium chloride electrolyte, which is expensive, highly corrosive, and extremely air-sensitive. Herein, we report a new hydrated eutectic electrolyte (HEE) composed of hydrated aluminum perchlorate and succinonitrile for low-cost, non-corrosive, and air-stable AIBs. The crystal water in hydrated aluminum perchlorate plays a vital role in forming the HEE, in which one H2 O and five SN and molecules coordinate with one Al3+ ion. The optimized ratio of Al(ClO4 )3 ·9H2 O to succinonitrile is 1:12. When combining with the self-doped polyaniline cathode, the associated AIB delivers a high discharge capacity of 185 mAh g-1 over 300 cycles; the charge/discharge mechanism in the HEE was studied experimentally and theoretically. The HEE is non-flammable, air-stable, and non-corrosive, thus enabling good air tolerance and facile fabrication of AIBs. This article is protected by copyright. All rights reserved.