Flexible solid state lithium batteries based on graphene inks

Different formulations of solution-processable graphene have been characterised as electrode materials for use in electrochemical energy storage devices. Graphene was fabricated by chemical reduction of exfoliated graphene oxide (GO), and modified with either p-type (e. g. polyaniline) or n-type anionic groups (poly(styrenesulfonate) (PSS(-)) and poly[2,5-bis(3-sulfonatopropoxy)-1,4-ethynylphenylene-alt-1,4-ethynylphenylene] sodium salt (PPE-SO(3)(-)) anion). Solutions of these graphene compounds were deposited on charge collecting electrodes and used as battery cathodes. Electrodes using the anionically-modified graphene inks containing anatase titanate (TiO(2)) nanoparticles show improved performance over pristine graphene ink as well as the p-type conducting polymer modified ones. In addition, the open circuit voltage of batteries based on TiO(2) has been boosted over 3 V with good cyclability when mixed with the graphene ink. Combined with a polymer electrolyte, this work suggests a feasible route towards fully printable rechargeable lithium batteries based on graphene inks. This approach is both versatile and scalable and is adaptable to a wide variety of applications.