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  • Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode NATURE COMMUNICATIONS Wang, D., Wei, C., Lin, M., Pan, C., Chou, H., Chen, H., Gong, M., Wu, Y., Yuan, C., Angell, M., Hsieh, Y., Chen, Y., Wen, C., Chen, C., Hwang, B., Chen, C., Dai, H. 2017; 8

    Abstract

    Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion-graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g(-1) with Coulombic efficiency ∼98%, at a current density of 99 mA g(-1) (0.9 C) with clear discharge voltage plateaus (2.25-2.0 V and 1.9-1.5 V). The cell has a capacity of 60 mAh g(-1) at 6 C, over 6,000 cycles with Coulombic efficiency ∼ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C-Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode.

    View details for DOI 10.1038/ncomms14283

    View details for Web of Science ID 000393751900001

    View details for PubMedID 28194027

  • High Coulombic efficiency aluminum-ion battery using an AlCl3-urea ionic liquid analog electrolyte PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Angell, M., Pan, C., Rong, Y., Yuan, C., Lin, M., Hwang, B., Dai, H. 2017; 114 (5): 834-839

    Abstract

    In recent years, impressive advances in harvesting renewable energy have led to a pressing demand for the complimentary energy storage technology. Here, a high Coulombic efficiency (∼99.7%) Al battery is developed using earth-abundant aluminum as the anode, graphite as the cathode, and a cheap ionic liquid analog electrolyte made from a mixture of AlCl3 and urea in a 1.3:1 molar ratio. The battery displays discharge voltage plateaus around 1.9 and 1.5 V (average discharge = 1.73 V) and yielded a specific cathode capacity of ∼73 mAh g(-1) at a current density of 100 mA g(-1) (∼1.4 C). High Coulombic efficiency over a range of charge-discharge rates and stability over ∼150-200 cycles was easily demonstrated. In situ Raman spectroscopy clearly showed chloroaluminate anion intercalation/deintercalation of graphite (positive electrode) during charge-discharge and suggested the formation of a stage 2 graphite intercalation compound when fully charged. Raman spectroscopy and NMR suggested the existence of AlCl4(-), Al2Cl7(-) anions and [AlCl2·(urea)n](+) cations in the AlCl3/urea electrolyte when an excess of AlCl3 was present. Aluminum deposition therefore proceeded through two pathways, one involving Al2Cl7(-) anions and the other involving [AlCl2·(urea)n](+) cations. This battery is a promising prospect for a future high-performance, low-cost energy storage device.

    View details for DOI 10.1073/pnas.1619795114

    View details for Web of Science ID 000393196300041

    View details for PubMedID 28096353

  • 3D Graphitic Foams Derived from Chloroaluminate Anion Intercalation for Ultrafast Aluminum-Ion Battery. Advanced materials Wu, Y., Gong, M., Lin, M., Yuan, C., Angell, M., Huang, L., Wang, D., Zhang, X., Yang, J., Hwang, B., Dai, H. 2016; 28 (41): 9218-9222

    Abstract

    A 3D graphitic foam vertically aligned graphitic structure and a low density of defects is derived through chloroaluminate anion intercalation of graphite followed by thermal expansion and electrochemical hydrogen evolution. Such aligned graphitic structure affords excellent Al-ion battery characteristics with a discharge capacity of ≈60 mA h g(-1) under a high charge and discharge current density of 12 000 mA g(-1) over ≈4000 cycles.

    View details for DOI 10.1002/adma.201602958

    View details for PubMedID 27571346

  • An ultrafast rechargeable aluminium-ion battery. Nature Lin, M., Gong, M., Lu, B., Wu, Y., Wang, D., Guan, M., Angell, M., Chen, C., Yang, J., Hwang, B., Dai, H. 2015; 520 (7547): 325-328

    Abstract

    The development of new rechargeable battery systems could fuel various energy applications, from personal electronics to grid storage. Rechargeable aluminium-based batteries offer the possibilities of low cost and low flammability, together with three-electron-redox properties leading to high capacity. However, research efforts over the past 30 years have encountered numerous problems, such as cathode material disintegration, low cell discharge voltage (about 0.55 volts; ref. 5), capacitive behaviour without discharge voltage plateaus (1.1-0.2 volts or 1.8-0.8 volts) and insufficient cycle life (less than 100 cycles) with rapid capacity decay (by 26-85 per cent over 100 cycles). Here we present a rechargeable aluminium battery with high-rate capability that uses an aluminium metal anode and a three-dimensional graphitic-foam cathode. The battery operates through the electrochemical deposition and dissolution of aluminium at the anode, and intercalation/de-intercalation of chloroaluminate anions in the graphite, using a non-flammable ionic liquid electrolyte. The cell exhibits well-defined discharge voltage plateaus near 2 volts, a specific capacity of about 70 mA h g(-1) and a Coulombic efficiency of approximately 98 per cent. The cathode was found to enable fast anion diffusion and intercalation, affording charging times of around one minute with a current density of ~4,000 mA g(-1) (equivalent to ~3,000 W kg(-1)), and to withstand more than 7,500 cycles without capacity decay.

    View details for DOI 10.1038/nature14340

    View details for PubMedID 25849777

  • An ultrafast rechargeable aluminium-ion battery NATURE Lin, M., Gong, M., Lu, B., Wu, Y., Wang, D., Guan, M., Angell, M., Chen, C., Yang, J., Hwang, B., Dai, H. 2015; 520 (7547): 325-?

    View details for DOI 10.1038/nature14340

    View details for Web of Science ID 000352974200033

    View details for PubMedID 25849777