Key Words:Sulfur compounds;Aluminum - Aluminum compounds - Cathodes - Electric discharges - Nickel compounds - Secondary batteries - Transition metals
Abstract:Transition metal sulfides are expected to be excellent candidates for aluminum batteries owing to their moderate polarity. Herein, Ni<inf>3</inf>S<inf>2</inf>/Ni cathode materials with unique morphology and good electrochemical performance has been successfully synthesized for aluminum battery by an effective chemical synthesis method. The galvanostatic charge/discharge measurement of the battery shows the initial discharge specific capacity of 236 mAh g⁻¹ at a current density of 10 mA g⁻¹, and it retains a reversible capacity of over 40 mAh g⁻¹ after 200 cycles, indicating a good capacity retention of the prepared electrode. More importantly, a two-step insertion mechanism of Al³⁺ in the Ni<inf>3</inf>S<inf>2</inf>/Ni cathode is put forward based on the experimental measurements and theoretical simulations. By calculation of the formation energy for Al<inf>x</inf>(Ni<inf>3</inf>S<inf>2</inf>)<inf>24</inf>, the single-tunnel insertion of Al³⁺ into the interstitial sites of Ni<inf>3</inf>S<inf>2</inf> at the higher discharge plateau and multi-tunnel at the lower one are deduced. This work not only provides an effective method, but also theoretical guidelines for the design and synthesis of promising cathode materials.<br/> © 2019 Elsevier B.V.
Volume:798
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Translation or Not:no