Rechargeable High-Capacity Antimony-Aluminum Batteries

Abstract

Rechargeable aluminum batteries are potentially the next generation energy storage systems, while they still suffer from unexpected positive electrodes for high-capacity aluminum batteries. For alleviating the specific capacity, in this study, antimony (Sb) is selected as the positive electrode for aluminum battery for its high theoretical capacity of 660 mAh g−1. For addressing dissolution issues of active Sb species into the electrolyte during the charge-discharge process, a special electrode design coupled with modified separators, the dissolution of Sb into liquid electrolyte is greatly suppressed. At a current density of 300 mA g−1, the specific discharge capacity can still reach 100 mAh g−1 after 1000 cycles, indicating the good long-term stability performance. More importantly, a systematical characterization is conducted to acquire a deep understanding of the energy storage mechanism of the Sb positive electrode. The characterization results from in situ Raman reveals that energy storage process involves the incorporation of AlCl4− into Sb to generate SbCl3/SbCl5. The results apparently highlight the strategies for designing high-performance Al-Sb batteries in a rational route.