N-doped C@ZnSe as a low cost positive electrode for aluminum-ion batteries: Better electrochemical performance with high voltage platform of ~1.8 V and new reaction mechanism

Abstract

Rechargeable aluminum-ion batteries (AIBs) are being extensively studied as a promising battery system due to their abundant resources and high theoretical capacity. However, the lack of suitable positive electrode materials with high electrochemical performances limits their practical application. Herein, a novel N-doped porous carbon/ZnSe composite (NC@ZnSe) with ZnSe nanoparticles evenly dispersed porous carbon derived from pyrolysis and selenization of ZIF-8 has been prepared for AIBs. The AIBs based on NC@ZnSe positive electrode not only deliver a high discharge specific capacity of 172.7 mAh g−1, but also provide a high discharge plateau at ~1.8 V vs. Al/Al3+, which is one of highest discharge plateaus for a transition metal chalcogenides electrode. Besides, Al/NC@ZnSe batteries present excellent cyclic stability with discharge specific capacity exceeds 70 mAh g−1 retained at 500 mA g−1 after 250 cycles. More importantly, the storage aluminum of NC@ZnSe is based on the conversion-alloying reaction mechanism, which is significantly different from the previously reported conversion or intercalation storage energy mechanism in AIBs. Therefore, the superior storage Al3+ performance of NC@ZnSe may be due to its unique conversion-alloying reaction mechanism. This work demonstrates that NC@ZnSe is a low-cost, naturally abundant, environmentally friendly electrode materials with high electrochemical performances for AIBs.