Mesoporous Reduced Graphene Oxide as a High Capacity Cathode for Aluminum Batteries

Abstract

Research in the field of aluminum batteries has focused heavily on electrodes made of carbonaceous materials. Still, the capacities reported for these multivalent systems remain stubbornly low. It is believed that a high structural quality of graphitic carbons and/or specific surface areas of >1000 m2 g‐1 are key factors to obtain optimal performance and cycling stability. Here an aluminum chloride battery is presented in which reduced graphene oxide (RGO) powder, dried under supercritical conditions, is used as the active cathode material and niobium foil as the current collector. With a specific surface area of just 364 m2 g‐1, the RGO enables a gravimetric capacity of 171 mAh g‐1 at 100 mA g‐1 and remarkable stability over a wide range of current densities (<15% decrease over 100 cycles in the interval 100–20000 mA g‐1). These properties, up to now achieved only with much larger surface area materials, result from the cathode's tailored mesoporosity. The 20 nm wide mesopores facilitate the movement of the chloroaluminate ions through the RGO, effectively minimizing the inactive mass content of the electrode. This more than compensates for the ordinary micropore volume of the graphene powder.

Beyond Lithium-Based Batteries

“…The most researched component for aluminum-ion batteries is the cathode. The research can be divided into six groups based on the type of material used for the cathode: metal oxides [127][128][129][130][131][132], metal sulfides [133][134][135][136][137], carbon [138,139], metal selenides [14,140] metal phosphides [141,142] and metal phosphite [143]. Here we highlight those works that focus on the function of the material.…”

“…It is generally believed that the structural quality of graphitic carbons assists in improving the performance of Al-ion batteries [146][147][148]. However, a different approach was also reported, where mesoporous reduced graphene oxide was designed and used as cathode to improve the performance of Al-ion batteries [139]. The material shows electrochemical performance comparable to that of material with much larger surface areas.…”

“…Another possible reason could be the porosity [137]. For carbon, the electrochemical properties are correlated to the surface area [139,[146][147][148]. Since this is a porous metal sulfide structure, rather than micro-or nanostructures, it could be The best results were obtained using nanosheet-bricked porous graphite as cathode, aluminum as anode and AlCl 3 in 1-ethyl-3-methylimidazolium chloride (1:1.3 mol) as ionic liquid electrolyte [138].…”

Rechargeable High‐Capacity Aluminum‐Nickel Batteries

“…designed the cell with 3D foam graphite cathode, which delivered a voltage platform up to 2 V and long‐term stability . Afterwards, a variety of carbon materials have been explored, mainly including edge‐rich graphene paper, mesoporous reduced graphene oxide, MOF‐derived carbon heterostructures, graphene aerogel derived compact films, polythiophene/graphite composites, graphene nanoribbons on highly porous 3D graphene, defect‐free soft carbon, amorphous carbon‐graphite composite, carbon nanoscrolls and commercial expanded graphite . All kinds of carbon materials exhibit a reversible capacity of 60–130 mA h g −1 and unparalleled cycle stability.…”

The Role of the Binder/Solvent Pair on the Electrochemical Performance of Aluminium Batteries

“…In a previous study, [2] we reported that the pore size distribution of the active material had a decisive effect on the electrochemical performance of aluminum chloride batteries (ACBs). Here, we show that the choice of the binder/solvent pair is another factor to carefully assess in the optimization of ACBs.…”