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The development of renewable energy schemes requires the scalable production of highly robust electrocatalysts using a sustainable synthesis process that does not generate toxic liquid wastes. Here...

Consumer grade supercapacitors as power supply resources require outstanding electrode materials with large conductivity, high durability and retention rates, as well as large capacity. Graphene is a promising functional material as an electrical double layer capacitance electrode due to its large surface area, high chemical stability and moderate conductivity. However, the existing graphene synthesis methods, including CVD and chemical exfoliation, are limited to lab scale production. Although laser induced graphene has demonstrated outstanding performance as an electrode material for microsupercapacitors, its difficulty to attach to the metallic current collector limits its application as a large capacity electrode material. Herein, laser induced forward transfer of graphene is developed for additively depositing laser induced graphene onto nickel foam as a composite electrode. The laser annealing enhanced the lattice matching between the extended Basal plane of graphene and Ni (111) resulting in its high electrical conductivity (359 712 S m−1), high retention rate (over 98% capacitance retention after 10 000 cycles), and large areal specific capacitance (995 mF cm−2) and power density (9.39 mW cm−2). The assembled supercapacitors with these additively printed electrodes can work as a USB charger with a stable 5 V output voltage, for charging smart phones and other smart devices.

Wearable sensing technologies are vital for realizing personalized health monitoring. Noninvasive human sweat sampling is essential for monitoring an individual's physical state using rich physiological data. However, existing wearable sensing technologies lack the controlled capture of body sweat and in performing on-device measurement without inflammatory contact. Herein, we report the development of a wearable sweat-capture device using patterned graphene arrays with controlled superwettability and electrical conductivity for simultaneously capturing and electrochemically measuring sweat droplets. The sweat droplets exhibited strong attachment on the superhydrophilic graphene patterns, even during moderate exercising. The captured sweat droplets present strong electrochemical signals using graphene films as the working electrode and metal pins as the counter electrode arrays assembled on 3D printed holders, at the detection limit of 6 μM for H2O2 sensing. This research enables full-body spatiotemporal mapping of sweat, which is beneficial for a broad range of personalized monitoring applications, such as drug abuse detection, athletics performance optimization, and physiological wellness tracking.