Electrochemical Performance of Tunnelled and Layered MnO₂ Electrodes in Aluminium-Ion Batteries: A Matter of Dimensionality

Abstract

Electrochemical activity of different MnO2 phases as electrodes of aluminium-ion batteries (AIBs) is studied. For this purpose, different simple synthesis routes have been carried out to obtain different structures and morphologies: rod-like with tunnelled structure (α-MnO2) and hexagonal micro-pellets with lamellar structure (δ-MnO2). α-MnO2 showed an outstanding capacity (Q) of 120 mA h g-1 at current densities of 100 mA g-1, which remained stable after 100 cycles with efficiencies over 90%. δ-MnO2 showed a good Q of 80 mA h g-1 at current densities of 50 mA g-1 after 50 cycles with efficiencies over 95%. Moreover, cyclic voltammetry (CV) measurements at different rates allowed for a better understanding of the electrochemical behaviour and revealed the contribution relation of diffusive and capacitive-controlled mechanisms in the corresponding AIB system. In addition, cyclic voltammetry (CV) measurements at different rates allowed a kinetic study of the diffusive and capacitive-controlled mechanisms. Conclusions were obtained regarding the dimensionality of α-MnO2 (1D) and δ-MnO2 (2D) and their electrochemical behaviour in AIBs.

Insight into the Storage Mechanism of Sandwich-Like Molybdenum Disulphide/Carbon Nanofibers Composite in Aluminum-Ion Batteries

“…In 2015, Lin introduced a model of AIBs utilizing a novel ionic liquid (AlCl 3 /[EMIm]Cl) as the electrolyte, marking a significant breakthrough in the field of AIBs [ 8 ]. Subsequently, various materials have been integrated into the cathode materials of non-aqueous AIBs, including metal oxides (such as MnO 2 and V 2 O 5 ) [ 9 , 10 ], transition metal chalcogenides (such as CuS 2 , VS 2 , and Co 9 S 8 ) [ 11 , 12 , 13 ], carbon-based materials (such as graphene, graphitic carbon, and graphitic foam) [ 14 , 15 , 16 ], and other materials (such as MXenes and conducting polymers) [ 17 , 18 ]. Among them, carbon-based materials are one of the most used in AIBs, with advantages such as high discharge voltage and good cycle stability.…”