Abstract
Sodium (Na) ion battery (NIBs) are considered as one of the most prospective battery system to substitute lithium ion batteries (LIBs) especially for stationary applications. In this study, rambutan peels were selected as carbon precursors to prepare hard carbons as anode materials for NIBs. Hard carbons were prepared by applying hydrothermal carbonization and then continued by the pyrolysis treatment at different temperatures (800, 1000 and 1200 °C). The electrochemical studies were carried out by cyclic voltammetry (CV) and galvanostatic charge discharge (GCD). The obtained hard carbons at pyrolysis temperature of 1000 exhibited the best electrochemical performance. It showed the highest reversible capacity of 225 mAh g−1 (0.1 C-rate, 1 C = 300 mA g−1) after 100 cycles if tested as the anode materials for NIBs. It is attributed to the disordered carbon structure, low degree of graphitization, large interlayer spacing and flake-like morphology of carbon sample which can provide more space for sodium storage and facilitate sodium ion transfer.