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Supercapacitors (SCs) are becoming new candidates in the field of sustainable energy supply. Nevertheless, the unsatisfactory energy density due to the narrow voltage window of the supercapacitor is the main barrier to its practical application. Developing appropriate electrode materials to improve the electrochemical performance of SCs and broaden the operating voltage of supercapacitors are imperative. Herein, compatible interfacial engineering wood-derived nanostructured electrodes for aqueous asymmetric supercapacitors (AASCs) are demonstrated. The 3D carbonized wood matrix serves as a high specific surface area current collector and a porous host for the high capacitive active substance, which is composed of manganese dioxide (MnO2) nanowires and polyaniline (PANI) nanoparticles grown uniformly on the porous wall of aligned microchannels (CW@MnO2 and CW@PANI). The resulting electrochemical exchange reactive sites enable the positive electrode to deliver a high areal capacitance of 729 mF cm−2 at 1 mA cm−2 (369 F g−1 at 0.5 A g−1). The negative electrode delivers a high areal capacitance of 1721 mF cm−2 at 1 mA cm−2 (848 F g−1 at 0.5 A g−1). The areal capacitance of two electrodes is superior to most reported supercapacitor electrodes. Additionally, the assembled CW@MnO2//CW@PANI AASC achieves a desirable energy density (170.84 μWh cm−2 at a power density of 0.5 mW cm−2) because a considerable work function difference between electrodes achieved a 2 V wide voltage window. The results of this study provide a critical benchmark and optimistic incentives to adopt natural hierarchical structures to enhance the performance of new-generation energy-related systems.

Abstract Biomaterials‐based electronic devices (BEDs) have remarkable advantages such as biocompatibility and biodegradability, which are expected to have promising prospects in the development of green electronics such as wearable smart sensors and brain‐like synaptic devices. However, the development of BEDs is still in its infancy, and much work remains to be done before this technology can be widely used. Here, a novel corn starch‐based BED with a sandwiched structure of Ag/Corn starch:PVDF/ITO is developed, which has integrated multifunctional performance of capacitive‐coupled memristive memory, flexible mechanical stress sensing, synaptic application, and logic operation. Specifically, this device exhibits a wide memristive voltage operating range (1–16 V), a high bending response current (3.5–4.5 µA), long‐term durability synaptic performance, and logic operation capability. These advantageous characteristics endow this device has a good potential to be used in flexible wearable electronics and artificial intelligence.