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Careful modulation of surficial and interfacial properties of electrode materials is a critical factor for determining overall electrochemical characteristics. Recent studies have indicated that metal oxide nanocoating layer (such as titanium (IV) oxide (TiO 2 )) on metal oxide anodes (such as tin (IV) oxide (SnO 2 )) exhibited superior electrochemical properties, but fundamental research on the effect and role of TiO 2 layer thickness has been limited. Here we have successfully conducted in-depth study on how the thickness of TiO 2 overlayer on SnO 2 can have significant influence in the overall parameters of electrochemistry. It is revealed that TiO 2 overlayer with 12 nm shows good cycle retention (75.8%) even after 80 cycles and retains capacity of 438.3 mAh g −1 even at high current density (5000 mA g −1 ). Surprisingly, it was further discovered that TiO 2 layer not only alleviates the volume expansion but also helps to facilitate Li ion transport compared with SnO 2 . The improvements in both ionic and electrical conductivity of TiO 2 layer are main factors in better cycle retention and rate capabilities. Finally, in situ transmission electron microscopy analysis was adopted to observe the growth dynamics of solid electrolyte interphase layer on TiO 2 @SnO 2 , which demonstrates that TiO 2 overlayer results in homogeneous and thinner interphase layer compared with SnO 2 NTs. [ABSTRACT FROM AUTHOR]

• 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]