Scalable top-down synthesis of functional carbon nanosheets by aronia fruit powder for Li+ and K+ storage.

• Novel top-down synthesis of CNS from aronia fruit powder by carbonization. • Temperature-independent synthesis of CNS. • Gas atmosphere-independent synthesis of CNS. • CNS exhibits high-rate cyclability for Li+ and K+ ion storage. • Structural integrity was well maintained even after cycling for Li+ and K+. Carbon nanosheets (CNSs) have been used in various applications, ranging from energy storage to drug delivery. CNSs are conventionally synthesized by chemical vapor deposition, but their high cost and non-scalability prompted the development of alternative synthesis routes. More scalable methods such as the sol-gel process still suffer from its complicated synthetic steps with delicate conditions. Here, we demonstrate for the first time a unique top-down synthesis of CNSs from aronia fruit powder, which is simple, scalable, and cost-effective. Aronia-derived CNS can be fabricated at various heating temperatures (500, 700, and 900 °C) and under different atmospheres (N 2 /H 2 and NH 3), which can easily tune the overall physicochemical properties of the CNS. We evaluated the electrochemical performance of the CNS for potential applications in Li- and K-ion batteries, in which the CNS showed stable electrochemical performance even at a high current density (1000 mA g−1). Because of the high-throughput nature of this synthetic approach, the aronia-derived CNSs could be very useful in developing novel applications at an industrial scale. [Display omitted] [ABSTRACT FROM AUTHOR]