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There is strong demand for higher energy density and flexible lithium ion batteries recently. Unfortunately, electrodes built by conventional methods cannot meet these requirements simultaneously due to the large amount of inactive additives needed for sufficient flexibility. Herein, by utilizing a continuous single‐walled carbon nanotube reticulation and designing an all‐in‐one hierarchical configuration, binder‐free electrodes are fabricated via an in situ integration procedure. The electrode exhibits excellent electrochemical performance against up to 20 000 cycles of bending and high energy density (up to 493 Wh kg−1electrode and 820 Wh L−1electrode). The hierarchical configuration takes full diverse advantages of different carbon nanostructures. The as‐obtained novel binder‐free electrodes exhibit not only good cyclability (up to ≈90% capacity retentions after 1500 cycles) with only 4 wt% additive materials, but also show enhanced kinetic process, in comparison to those of traditional electrodes. Furthermore, based on the as‐designed electrodes, flexible cells are assembled and a practical wearable system is fabricated, manifesting that they can be used in a stable and flexible power supply for smart systems. [ABSTRACT FROM AUTHOR]

Recent development in epidermal and bionic electronics systems has promoted the increasing demand for supercapcacitors with micrometer-thickness and good compatibility. Here, a highly flexible free-standing epidermal supercapacitor (SC-E) with merely 1 μm thickness and high performance is developed. Single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) hybrid films with unique inner-connected reticulation are adopted as electrodes for ultrathin structure and high electric conductivity. Then, based on two substrates with different surface energies, a stepwise lift-off method is presented to peel off the ultrathin integrated supercapacitor from the substrates nondestructively. As a result of the high conductive hybrid electrodes and the thin electrolyte layer, the as-designed supercapacitors (based on the total mass of two electrodes) achieve a good capacitance of 56 F g−1 and a superhigh power density of 332 kW kg−1, which manifest superior performance in contrast to the other devices fabricated by traditional electrodes. Meanwhile, the ultrashort response time of 11.5 ms enables the epidermal supercapacitor (SC-E) work for high-power units. More importantly, the free-standing structure and outstanding flexibility (105 times bending) endow the SC-E with excellent compatibility to be integrated and work in the next generation of smart and epidermal systems. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs), also called electrochemical capacitors, often show high power density, excellent charge/discharge rates, and long cycle life. The recent development of flexible and wearable electronic devices requires that their power sources be sufficiently compact and flexible to match these electronic components. Therefore, flexible SCs have attracted much attention to power current advanced electronics that can be flexible and wearable. In the past several years, many different strategies have been developed to programmably construct different nanocarbon materials into bendable electrode architectures. Furthermore, flexible SC devices with simplified configurations have also been designed based on these nanocarbon-based architectures. Here, recent developments in the programmable assembly of bendable architectures based on nanocarbon materials are presented. Additionally, the design of flexible nanocarbon-based SC devices with various configurations is highlighted. The progress made recently paves the way for further development of nanocarbon architectures and corresponding flexible SC devices. Future development and prospects in this area are also analyzed. [ABSTRACT FROM AUTHOR]