Chloroaluminate Anion Intercalation in Graphene and Graphite: From Two-Dimensional Devices to Aluminum-Ion Batteries

Abstract

A rechargeable aluminum-ion battery based on chloroaluminate electrolytes has received intense attention due to the high abundance and chemical stability of aluminum. However, the fundamental intercalation processes and dynamics in these battery systems remain unresolved. Here, the energetics and dynamics of chloroaluminate ion intercalation in atomically thin single crystal graphite are investigated by fabricating mesoscopic devices for charge transport and operando optical microscopy. These mesoscopic measurements are compared to the high-performance rechargeable Al-based battery consisting of a few-layer graphene–multiwall carbon nanotube composite cathode. These composites exhibit a 60% capacity enhancement over pyrolytic graphite, while an ∼3-fold improvement in overall ion diffusivity is also obtained exhibiting ∼1% of those in atomically thin single crystals. Our results thus establish the distinction between intrinsic and ensemble electrochemical behavior in Al-based batteries and show that engineering ion transport in these devices can yet lead to vast improvements in battery performance.

Investigation of Si-Coated Multiwalled Carbon Nanotubes as Potential Electrodes for Multivalent Metal-Ion Electrochemical Energy Storage Systems

“…Although Al 3+ ions diffuse faster (as diffusion coefficient values indicated) due to smaller ionic radius, the extracting process could not be entirely reversible as agglomerations of smaller ions held in the electrode structure limit ion release. In particular, the 1.1 Si/MWCNT is exhibiting similar ion mobility kinetics, compared to the transport of AlCl 4 – in Al-PTh/MWCNT (0.65 × 10 –10 and 1.39 × 10 –10 cm 2 s –1 for oxidation and reduction processes, respectively), and smaller kinetics for PG (7.8 × 10 –9 cm 2 s –1 ), FLG@PG (1.37 × 10 –8 cm 2 s –1 ), FLG/CNT@PG (1.94 × 10 –8 cm 2 s –1 ), and thin graphite layers (9.6 × 10 –6 cm 2 s –1 at 320 K) …”

“…In particular, the 1.1 Si/MWCNT is exhibiting similar ion mobility kinetics, compared to the transport of AlCl 4 − in Al-PTh/MWCNT (0.65 × 10 −10 and 1.39 × 10 −10 cm 2 s −1 for oxidation and reduction processes, respectively), 84 and smaller kinetics for PG (7.8 × 10 −9 cm 2 s −1 ), FLG@PG (1.37 × 10 −8 cm 2 s −1 ), FLG/CNT@PG (1.94 × 10 −8 cm 2 s −1 ), and thin graphite layers (9.6 × 10 −6 cm 2 s −1 at 320 K). 85 Because trivalent Al 3+ ions have significant electrostatic interaction with host materials, it is challenging to find ideal electrodes with high capacity and acceptable rate performance when producing AHCs. As mentioned in the Introduction section, Wang et al 33 fabricated an AHC that functioned in Al 2 (SO 4 ) 3 aqueous electrolyte from 0 to 1.5 V and showed evidence of Al 3+ intercalation/de-intercalation into/from the anode with very low capacity at the cathode and enhanced energy density.…”

Study of In-Plane and Interlayer Interactions During Aluminum Fluoride Intercalation in Graphite: Implications for the Development of Rechargeable Batteries

“…Renewable and sustainable energy storage technologies are nowadays a strategy to mitigate climate change, environmental pollution, and fossil fuel scarcity. , Electrochemical energy storage, particularly rechargeable batteries, is considered one of the solutions to supply or back up clean electricity in portable devices. While lithium-based rechargeable batteries have been developed for various applications and successfully commercialized, much research has focused on exploring alternative materials that are abundant in nature and less reactive, which reduces self-ignition risk. , In this sense, research on alternatives to lithium (Li) in rechargeable batteries is dominated mainly by systems with sodium (Na), , magnesium (Mg) , or aluminum (Al). − The anode material is equally important to charge carrier ions. Graphite shows potential as an anode material for rechargeable metal-ion batteries because of its high abundance and low cost. , The systems with superior rate performance and cycling stability are obtained through a unique potassium–solvent cointercalation mechanism in natural graphite .…”

Lewis Acid-Induced Reversible Disproportionation of TEMPO Enables Aqueous Aluminum Radical Batteries

“…Early work on AIBs using graphitic carbon or other metal-based oxides as cathodes evidence that a slow diffusion and insertion of large Al 3+ complexes is the major hurdle for the application of AIBs . As a result, many studies have been focused on understanding and improving the diffusivity and intercalation/deintercalation of Al 3+ complexes to address their low cathode efficiency and poor voltage output. − …”