Synthesis of high voltage cathode materials for aqueous Al-ion battery

Abstract

The opportunity of exploring aluminium-ion batteries (AIBs) has surfaced in anticipation of future societal demand for high energy density and affordable batteries. AIBs are exceptionally attractive as aluminium is envisioned to provide a low-cost energy storage platform, due to its abundance in Earth’s crust. Additionally, the high volumetric capacity of aluminium (8046 mAh cm-3) [1] which is four to seven times larger than Lithium and Sodium, undoubtedly has the potential to drive the energy density of AIBs further on a per unit volume. Moreover, the potential safety hazard is reduced as Aluminium has better air stability as compared to Lithium. However aqueous systems of AIBs have exhibited fatal drawbacks [2]. Thus this provides a new prospect to discover a new synthesis of cathodic material to further optimize the cell efficiency of AIBs. This report investigates new and uncommercialized cathodic materials – Manganese Oxide (MnO2) through characterization techniques as well as evaluating coin cells at discharge rates with Ionic-Liquid Aluminium (ILA) as the anode.

Four cathodic materials MnO2 were synthesized, namely Titanium-MnO2 (Ti-MnO2), Aluminium-MnO2 (Mn3O4), Potassium-MnO2 (K-MnO2) as well as commercialized MnO2. Synthesis of the cathodic materials were performed by hydrothermal process and deposition method. The purity was investigated through X-Ray Diffraction (XRD) characterization. Cell assembly of the cathodic MnO2, Ionic Liquid Aluminium (ILA) anode and ionic separator Aluminum Trifluoromethanesulfonic acid (ALTFS) was performed. The charge capacity of the AIBs cell was conducted by the Cyclic Voltammetry (CV) and the Galvanostatic Charge Discharge (GCD) equipment.