▎ 摘　　要

Here, a controlled green synthesis route involving hydrothermal pre-carbonization cum pyrolysis is reported that converts cucumber into graphene-like carbon nanosheets for supercapacitor application. Transmission electron microscopy analysis reveals the formation of ultra-thin carbon nanosheets with distributed pores. This cucumber derived carbon exhibits high specific capacitance of 143 Fg(-1) in aqueous electrolyte. The two-electrode symmetric cell exhibits a specific capacitance of 58 Fg(-1) at high current density, and high capacitance retention of 97% after 1000 cycles. This simple low-cost process involving widely available cucumber as biomass precursor is a promising, commercially viable approach for developing high-performance supercapacitors. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.