Aqueous aluminum-ion batteries based on layered NH4V4O10 nanosheets as cathode

Abstract

Aluminum, known as a natively abundant and trivalent charge carrier, has a high volumetric density and theoretical specific capacity. Due to these characteristics, aluminum-ion batteries are recognized as a prospective technology for large-scale energy storage in the future. However, the practical applicability of aluminum ion batteries has been hindered by the confirmed decline of the electrode host structure and the slow diffusion kinetics of aluminum ion. Here, in this work, layered NH4V4O10 nanosheets cathode materials were first applied to the aqueous aluminum-ion battery. Thanks to the interlayer support of NH4+, which acts as a “pillar”, the sample demonstrates a high capacity of 257.78 mA h g−1 at a current density of 0.5 A g−1 and excellent rate performance of 87.80 mA h g−1 at a current density of 5 A g−1. Besides, the evolution of electrode crystal/electronic structure and the charge compensation mechanism during Al3+ intercalation/deintercalation have been investigated through systematic experimental measurements and theoretical computations. This work is anticipated to provide fresh perspectives and more thorough insights into exploration of competent cathode material and charge storage mechanisms for aqueous aluminum-ion batteries with high electrochemical properties.