LAUSR

Stretchable energy storage devices are prerequisites for the realization of autonomous elastomeric electronics. Microsupercapacitors (MSCs) are promising candidates for this purpose due to their high power and energy densities, potential for miniaturization, and feasibility of embedding in circuits; however, efforts to realize stretchable MSCs have mostly relied on strain-accommodating materials and have suffered from limited stretchability, low conductivity, or complicated patterning processes. Here, we designed and fabricated a stretchable MSC based on reduced-graphene-oxide/Au heterostructures patterned by facile and versatile direct laser patterning. An interconnected and stable 3D network composed of vertically oriented heterostructures was realized by high-repetition-rate femtosecond laser pulses. Upon transferring to polydimethylsiloxane (PDMS), the 3D network achieved a high conductivity of ~105 S m−1, and the conductivity could be maintained at ~104 S m−1 even at 50% strain. A fully laser-patterned stretchable electronics system was integrated with embedded MSCs, which will find applications in soft robotics, wearable electronics, and the Internet of Things.Graphene oxide: Spiky structures for stretchy energy storageBy transforming flat graphene oxide films into vertically oriented sheets, researchers have constructed an energy storage device that may power wearable electronics. Graphene oxide’s ability to quickly store and release charge from its surface makes it attractive for supercapacitors, which recharge significantly faster than conventional batteries. Young-Jin Kim and Pooi See Lee from the Nanyang Technological University in Singapore and colleagues have now used ultrafast lasers to controllably heat graphene oxide into a spiky 3D network that accommodates large amounts of mechanical strain. Following deposition of a gold coating and subsequent transfer to an elastomeric substrate, the team’s supercapacitor retained its high energy output even after being rolled, bent, twisted, and crumpled hundreds of times. The laser-based fabrication enabled production of customized patterns, such as wavy electrode ‘fingers’ that can attach to curved surfaces.An intrinsically stretchable and highly conductive graphene electrode based on vertically oriented graphene/Au bilayer flakes are successfully fabricated by a direct-laser-patterning at a very high-repetition rate and fast scanning speed of laser with a femtosecond pulse, allowing micro-supercapacitors to be integrated with the complete soft electronics systems that can be standalone and be customized by user’s circuit designs.