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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]

Asymmetric supercapacitors with high energy density are fabricated using a self-assembled reduced graphene oxide (RGO)/MnO2 (GrMnO2) composite as a positive electrode and a RGO/MoO3 (GrMoO3) composite as a negative electrode in safe aqueous Na2SO4 electrolyte. The operation voltage is maximized by choosing two metal oxides with the largest work function difference. Because of the synergistic effects of highly conductive graphene and highly pseudocapacitive metal oxides, the hybrid nanostructure electrodes exhibit better charge transport and cycling stability. The operation voltage is expanded to 2.0 V in spite of the use of aqueous electrolyte, revealing a high energy density of 42.6 Wh kg−1 at a power density of 276 W kg−1 and a maximum specific capacitance of 307 F g−1, consequently giving rise to an excellent Ragone plot. In addition, the GrMnO2//GrMoO3 supercapacitor exhibits improved capacitance with cycling up to 1000 cycles, which is explained by the development of micropore structures during the repetition of ion transfer. This strategy for the choice of metal oxides provides a promising route for next-generation supercapacitors with high energy and high power densities. [ABSTRACT FROM AUTHOR]