Highly stretchable graphene-nanocellulose composite nanopaper is fabricated for strain-sensor applications. Three-dimensional macroporous nanopaper from crumpled graphene and nanocellulose is embedded in elastomer matrix to achieve stretchability up to 100%. The stretchable graphene nanopaper is demonstrated for efficient human-motion detection applications.

Well-separated RGO sheets decorated with MnO2 nanoparticles facilitate easy access of the electrolyte ions to the high surface area of the paper electrode, enabling the fabrication of a thicker electrode with heavier areal mass and higher areal capacitance (up to 897 mF cm(-2) ). The electrochemical performance of the bent asymmetric device with a total active mass of 15 mg remains similar to the one in the flat configuration, demonstrating good mechanical robustness of the device.

Stretchable and wearable WO3 electrochromic devices on silver nanowire (AgNW) elastic conductors are reported. The stretchable devices are mechanically robust and can be stretched, twisted, folded, and crumpled without performance failure. Fast coloration (1 s) and bleaching (4 s) time and good cyclic stability (81% retention after 100 cycles) were achieved at relaxed state. Proper functioning at stretched state (50% strain) was also demonstrated. The electrochromic devices were successfully implanted onto textile substrates for potential wearable applications. As most existing electrochromic devices are based on rigid technologies, the innovative devices in their soft form hold the promise for next-generation electronics such as stretchable, wearable, and implantable display applications.

Fabrication of intrinsically stretchable nanowire photodetectors based on fully embedded structures is reported. A lithographic filtration method is used to integrate different functional layers into the photodetectors, which exhibit excellent stretchability up to 100%. The fully embedded structure enables excellent stability against repeated stretching, mechanical scratching, and adhesive forces.

shown template-free approaches. [13][14][15][16][17][18][19][20] Particular interest on fabricating freestanding graphene supercapacitor electrode has received notable attention since the removal of current collector is particularly effective in lowering equivalent series resistance (ESR) and in turn allowing a higher loading density. [ 14,[20][21][22] Wang et al. reported graphene paper electrodes with promising performance up to 147 F g −1 (64 F cm −3 ) for energy storage applications. [ 14 ] Self-stacked solvated graphene has also been shown to achieve 215 F g −1 , claiming fast ion diffusion with very low ESR. [ 20 ] In the meantime, an increasing number of transition metal oxides composites with carbon-based materials for energy storage applications has been reported in literatures, [22][23][24][25][26][27][28] whereby both types of charge storage mechanisms can be harnessed. Zhao et al. have recently reported V 2 O 5 -rGO composites for supercapacitors and Li-ion batteries [ 29 ] which exhibited excellent cycling performance and high specifi c capacity. However, the ESR was rather high due to the presence of impurities in the slurry, with high contact resistance between active material and current collector. In this work, we introduce the concept of a free-standing electrode which eliminates redundant dead cell components such as binders and current collectors as they contribute to unnecessary contact resistance and equivalant series resistance (ESR). Li et al. have demonstrated freestanding MnO 2 -graphene electrodes exhibiting a performance of 256 F g −1 at a current density of 0.5 A g −1 . [ 17 ] Despite being a free-standing electrode, the reported mass (0.07 mg) was much lower than the usual mass of slurry electrodes. The exposed area of the active electrode was also less than 1 cm 2 . This shows that the intrinsic capacitance of the material is rather low and will demand large amount of active material to achieve the required capacitance to power up commercial devices. Efforts towards high loading mass include graphene/CNT/MnO 2 composite free-standing fi lms with loading density of 2.02 mg cm −2 with specifi c capacitance of 326 F g −1 at scan rate of 10 mV s −1 . [ 18 ] In our recent work, specifi c capacitance of 245 F g −1 was reported for MnO 2 -rGO free-standing composites with an electrode mass loading of 3.6 mg cm −2 . [ 30 ] These high mass loading electrodes give more realistic candidate for scalability as it is closer to the actual mass content of commercial products. Sole comparisons made based on gravimetric capacitance would not be appropriate due to signifi cantly lower masses used in some reports. Furthermore, gravimetric capacitance does not scale proportionally with increasing mass. Therefore, areal capacitance offers a favorable benchmark to establish understanding on the effect of Vanadium pentoxide-reduced graphene oxide (rGO) free-standing electrodes are used as electrodes for supercapacitor applications, eliminating the need for current collectors or additives and reducing resis...