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 similar to 0.15 kO/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 similar to 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 similar to 40% of the above reversible capacity at 5C. Furthermore, the electrode could retain similar to 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.

Automated summary

In this study, large-area continuous graphene films were fabricated on different substrates via inkjet printing using solvent-exfoliated graphene nanosheets and associated printable ink. Thermal annealing in Ar improved electrical conductivity and embedded porosity, with sheet resistance decreasing with an increase in the number of printed layers. The inkjet-printed graphene film showed promising potential as an anode for Li-ion batteries, exhibiting high reversible Li storage capacity and good rate capability.