Porous α-MnSe Microsphere Cathode Material for High-Performance Aluminum Batteries

Graphical Interc-Al-ation for batteries : A high-capacity cathode with porous α-MnSe is designed for rechargeable aluminum batteries. The fundamental reaction mechanism of the α-MnSe cathode is deeply researched in the manuscript. The synergistic effect of nanostructure and porosity could efficiently mitigate volume changes of the α-MnSe and enhance intercalation kinetics of Al 3+ , which sheds new light on the establishment of advanced energy-storage devices. Aluminum batteries (ABs) have been considered as a viable candidate for new-generation energy-storage devices due to its low cost and high theoretical volumetric capacity. Despite these advantages, the large-scale application of ABs is constrained by scarce options of suitable cathode materials. Herein, three-dimensional nanostructured α-MnSe microspheres with porous properties are reported as a cathode for ABs. The nanosized and porous structure of α-MnSe could offer numerous open channels and the short ionic transport path, which would efficiently mitigate volume changes and enhance electrochemical reaction kinetics. Moreover, the pseudocapacitive characteristic of Al 3+ storage in α-MnSe contributes to the fast kinetics of the cathode. It is demonstrated that the reversible Al 3+ insertion/extraction occurs in the α-MnSe cathode during the cycling process. The resulting aluminum battery based on the α-MnSe cathode, AlCl 3 /[EMIm]Cl ionic liquid electrolyte, and aluminum anode exhibits an ultrahigh reversible capacity of 408 mA h g −1 at 0.2 A g −1 . Even for a current density at 1 A g −1 , a discharge capacity of 131 mA h g −1 could be retained with a Coulombic efficiency of 97 % over 150 cycles. This strategy has referential significance in aspects of the selection of compatible cathode for ABs.