h-MoO3/AlCl3-Urea/Al: High performance and low-cost rechargeable Al-ion battery

Abstract

A completely functional rechargeable aluminium – ion battery (AIB) operating at room temperature based on hexagonal molybdenum oxide (h-MoO3) as positive electrode active material and AlCl3-Urea as electrolyte has been developed. This is the first demonstration of the compatibility between a metal oxide and a urea based electrolyte in an AIB. Our battery shows a good electrochemical performance by using this low-cost, eco-friendly, positive electrode - electrolyte system with low corrosion properties. Thanks to an exhaustive study carried out by using different characterization techniques (XRD, micro-Raman, CV), it has been observed that h-MoO3 is capable of efficiently inserting and de-inserting the redox active species in its crystalline structure by means of controlled diffusion processes. When combined with a suitable amount of carbon nanotubes, the capacitive properties of this material are enhanced, obtaining batteries with a pseudo-capacitive behaviour. This battery reaches specific capacity values ∼100 mA h g−1 at current densities of 100 mA g−1 and ∼45 mA h g−1 at current densities of 500 mA g−1, always with efficiencies higher than 90%. The obtained results pave the way for the commercialisation of these energy storage devices, providing a promising and simple strategy for the development of high performance, low-cost and non-corrosive AIBs.