Porous Graphene Films with Unprecedented Elastomeric Scaffold‐Like Folding Behavior for Foldable Energy Storage Devices

• Published in: Advanced materials (Weinheim) 2018-05, Vol.30 (21), p.e1707025-n/a
• Main Authors: Huang, Ruling, Huang, Meiling, Li, Xiaofeng, An, Fei, Koratkar, Nikhil, Yu, Zhong‐Zhen
• Format: Article
• Language: English
• Subjects: Annealing; elastomeric scaffold‐like folding; Elastomers; Electronic devices; Energy storage; foldable supercapacitors; Folding; Graphene; Liquid nitrogen; Materials science; Oxide coatings; Plastic deformation; porous graphene films; Scaffolds
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201707025

The development of fully foldable energy storage devices is a major science and engineering challenge, but one that must be overcome if next‐generation foldable or wearable electronic devices are to be realized. To overcome this challenge, it is necessary to develop new electrically conductive materials that exhibit superflexibility and can be folded or crumpled without plastic deformation or damage. Herein, a graphene film with engineered microvoids is prepared by reduction (under confinement) of its precursor graphene oxide film. The resultant porous graphene film can be single folded, double folded, and even crumpled, but springs back to its original shape without yielding or plastic deformation akin to an elastomeric scaffold after the applied stress is removed. Even after thermal annealing at ≈1300 °C, the folding performance of the porous graphene film is not compromised and the thermally annealed film exhibits complete foldability even in liquid nitrogen. A solid‐state foldable supercapacitor is demonstrated with the porous graphene film as the device electrode. The capacitance performance is nearly identical after 2000 cycles of single‐folding followed by another 2000 cycles of double folding. A graphene film with microvoids is prepared by reduction of graphene oxide film. It can be double folded and even crumpled, but springs back to its original shape without yielding or plastic deformation akin to an elastomeric scaffold. When used as the electrodes of a solid‐state supercapacitor, the capacitance performance is nearly identical after 2000 cycles of single folding, followed by another 2000 cycles of double folding.