Inkjet-Printed Environmentally Friendly Graphene Film for Application as a High-Performance Anode in Li-Ion Batteries

We report here the fabrication of large-area continuous graphene films on different substrates via inkjet printing using “solvent-exfoliated” graphene nanosheets and associated printable ink prepared with the nanosheets in “green solvent” (i.e., ethanol) and ethyl-cellulose (as a stabilizer). The printed film was thermally annealed in Ar to improve the electrical conductivity and embed well-defined porosity. Sheet resistance decreased with an increase in the number of printed layers, attaining a low value of ∼0.15 kΩ/sq after 8 printing cycles. When printed on Cu foil and directly tested as a potential anode for Li-ion batteries, a high reversible Li storage capacity of ∼942 mAh/g could be obtained at 0.1C based on dual contributions from “classical” Li-intercalation/deintercalation and surface charge storage. The nanoscaled dimension and porous nature aided the latter, which also resulted in good rate capability, leading to ∼40% of the above reversible capacity at 5C. Furthermore, the electrode could retain ∼87% of the initial reversible capacity after 100 cycles, even at a fairly high current density equivalent to 2C. Overall, the inkjet-printed graphene film, by itself, is a promising anode for Li-ion batteries, with the development likely to aid a variety of important applications, including flexible devices and energy storage systems.