Ultrafast Charging High Capacity Asphalt-Lithium Metal Batteries.

Wang, Tuo; Villegas Salvatierra, Rodrigo; Jalilov, Almaz S; Tian, Jian; Tour, James M · ACS Nano · 2017

basic_science · Level V

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Abstract

Li metal has been considered an outstanding candidate for anode materials in Li-ion batteries (LIBs) due to its exceedingly high specific capacity and extremely low electrochemical potential, but addressing the problem of Li dendrite formation has remained a challenge for its practical rechargeable applications. In this work, we used a porous carbon material made from asphalt (Asp), specifically untreated gilsonite, as an inexpensive host material for Li plating. The ultrahigh surface area of >3000 m<sup>2</sup>/g (by BET, N<sub>2</sub>) of the porous carbon ensures that Li was deposited on the surface of the Asp particles, as determined by scanning electron microscopy, to form Asp-Li. Graphene nanoribbons (GNRs) were added to enhance the conductivity of the host material at high current densities, to produce Asp-GNR-Li. Asp-GNR-Li has demonstrated remarkable rate performance from 5 A/g<sub>Li</sub> (1.3C) to 40 A/g<sub>Li</sub> (10.4C) with Coulombic efficiencies >96%. Stable cycling was achieved for more than 500 cycles at 5 A/g<sub>Li</sub>, and the areal capacity reached up to 9.4 mAh/cm<sup>2</sup> at a highest discharging/charging rate of 20 mA/cm<sup>2</sup> that was 10× faster than that of typical LIBs, suggesting use in ultrafast charging systems. Full batteries were also built combining the Asp-GNR-Li anodes with a sulfurized carbon cathode that possessed both high power density (1322 W/kg) and high energy density (943 Wh/kg).