Electrochemical study of TiO2 in aqueous AlCl3 electrolyte via vacuum impregnation for superior high-rate electrode performance

Metal-Organic Framework for Aluminum based Energy Storage Devices: Utilizing Redox Additives for Significant Performance Enhancement

There are various methods being tried to address the sluggish kinetics observed in Al-ion batteries (AIBs). They mostly deal with morphology tuning, but have led to limited improvement. A new approach is proposed to overcome this limitation. It focuses on the use of a redox additive modified electrolyte in combination with framework like materials, which have wider channels. The ordered microporous and interconnected framework of ZIF 67, with large surface area, effectively facilitates the diffusion of aluminum ions. Therefore, AIBs are able to exhibit a superior discharge capacity of 288 mAh g-1 at 0.2 A g-1 current density with robust cycling stability. The addition of potassium ferricyanide as a redox-active species in an aqueous solution of aluminum chloride (supporting electrolyte) leads to significant enhancement in the specific capacity with much higher cycling stability. Al-ion based BatCap devices can be assembled by using ZIF 67 as the cathode, ZIF 67 derived porous carbon as the anode, and a redox additive modified electrolyte. The BatCap device exhibits excellent energy density of 86 Wh kg-1 at a power density of 2 KW kg-1, which is higher than reported aqueous AIBs. The ex situ characterization clearly explains the unexplored mechanism of redox additives in AIBs.

A Review of Energy Storage Mechanisms in Aqueous Aluminium Technology

This systematic review covers the developments in aqueous aluminium energy storage technology from 2012, including primary and secondary battery applications and supercapacitors. Aluminium is an abundant material with a high theoretical volumetric energy density of –8.04 Ah cm−3. Combined with aqueous electrolytes, which have twice the ionic storage potential as non-aqueous versions, this technology has the potential to serve many energy storage needs. The charge transfer mechanisms are discussed in detail with respect to aqueous aluminium-ion secondary batteries, where most research has focused in recent years. TiO2 nanopowders have shown to be promising negative electrodes, with the potential for pseudocapacitive energy storage in aluminuim-ion cells. This review summarises the advances in Al-ion systems using aqueous electrolytes, focusing on electrochemical performance.