Facile synthesis of carbon nanobranches towards cobalt ion sensing and high-performance micro-supercapacitors

We present a facile strategy for fabricating a new type of one-dimensional (1D) carbon nanomaterial named carbon nanobranches (CNBs) covered with botryoidal carbon dots (CDs) by direct pyrolysis of a green precursor (starch). The resultant CNBs display both photoluminescence and electrical conductivity and can be assembled into chemical sensors and energy-storage devices. In terms of their bright photoluminescence, CNBs with a fabulous crystalline structure are utilized as fluorescent probes to sensitively and selectively detect Co²⁺ with a very low detection limit of 2.85 nM and a wide linear concentration range from 10 nM to 1 mM. Moreover, an efficient micro-supercapacitor (micro-SC) is constructed based on conductive CNB fibers produced via a customized microfluidic spinning technique. The micro-SCs exhibit a large specific capacitance of 201.4 mF cm^-2, an energy density of 4.5 μW h cm^-2 and high cycling stability, and can successfully power 19 light-emitting diodes (LEDs). The main purpose of this paper is to offer a perspective into simplifying the connecting of research and industry by starting from green carbon-based materials.