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Highlights • Ultrafine porous carbon/MnO 2 nanowires were expected to shorten the ion diffusion path. • The carbon aerogel derived from methyl cellulose provides a cost-consuming system. • The hierarchical structure serves as stable framework to reduce the agglomeration. • The composite can be stamped into arbitrary patterns to be applied in micro-devices. Abstract A green and scaled-up strategy has been successfully employed to fabricate asymmetric supercapacitors (ASC) in conjunction with high energy density as well as highly efficient electrode materials. In this study, a B, N-dual doped porous carbon aerogel negative and a novel ultrafine nanowire positive composite, composed of manganese oxide (MnO 2) core and carbon aerogel shell, were proposed. Methyl cellulose (MC) is spaciously available and the affluent hydroxyl groups on the molecular chains are conductive to trigger supramolecular assemble process to form self-crosslinking hydrogel. And then the hydrogel was dried and carbonized to obtain the B, N-dual doped porous carbon aerogel (BN-MC), with the specific area of 989.8 m2 g−1. Subsequently, a facile and efficient hydrothermal system, introduced to synthesize BN-MC/α-MnO 2 composite, is prone to achieve hybrid nanowires with an average width of ∼15 nm. The prepared 0.1BN-MC/MnO 2 -8 sample (0.1 M NH 4 HB 4 O 7 doping agent and 8 mg BN-MC addition) exhibits highest electrochemical behavior, whose capacitance is up to 338 F g−1 at 1 A g−1. That is ascribed to the well-dispersed α-MnO 2 nanowires and uniformly cladding BN-MC shell. The ASC, assembled with BN-MC/MnO 2 and BN-MC, significantly enhances energy density reaching to 27.75 Wh kg−1 at a power density of 1.35 kW kg−1 operating under 1.8 V voltage window. This ASC also shows superior cycling stability for maintaining 95.6% initial capacitance after 2000 cycles. What's more, the BN-MC/MnO 2 can be stamped into arbitrary patterns in seconds. This provides a new rapid prototyping technology for fabricating flexible and portable micro-supercapacitor devices. [ABSTRACT FROM AUTHOR]

The novel Sn-Cu nanotubes enveloped in three-dimensional (3D) hierarchical polyaniline (PANI) hydrogel (Sn-Cu/PANI) were successfully prepared as a high performance anode for lithium-ion battery. The binder-free electrode exhibits reversible capacity of 548 mA h g −1 after 500 cycles and admirable rate capacity even up to 5000 mA g −1 . The exceptional electrochemical performance of Sn-Cu/PANI hydrogel could be attributed to the unique structure: (1) The inactive Cu matrix in binary Sn-Cu compounds and the tubular construction conduce to relieve the volume swing; The high porosity originated from galvanic replacement reaction accelerates ions transmission, which contributes to rapid charging and discharging. (2) The 3D porous PANI framework offers a continuous electron and lithium ions transport network among the whole electrode; the hierarchical PANI serves as mechanical support to accommodate the stress related to the large volume change of Sn-Cu nanotubes, thus reducing the risk of electrode pulverization. [ABSTRACT FROM AUTHOR]