Olive leave-derived hard carbon materials for Li/Na-ion battery and supercapacitor applications.

Some of the most practical technologies for storing and converting electrochemical energy include Li-ion batteries (LIBs), Na-ion batteries (NIBs) and electrochemical supercapacitors 1 (ES) . LIBs are the most developed energy storage devices which are often used in portable electronics, in electric vehicles and stationary battery storage systems.NIBs are commonly 2 used in large-scale electrical energy storage . Currently, NIBs have drawn significant attention as a potential alternative for LIBs, despite their lower performance, because of to the lower cost, similar electrochemical properties and higher abundance of sodium. ESs complement batteries by providing back up power supplies and the necessary power for 2,3 acceleration and brake energy in hybrid electric vehicles . The Industrial Revolution began in the 18th century, when agricultural societies became more industrialized and urban. Since then, products have been designed in a linear model from cradle to grave, from production to consumption to waste. Now, the market starts to understand it can create value by reusing and recycling products in a closed loop whereby 2 they don"t become waste, but key resources again . Hard-carbons (non-graphitized carbons) which are produced from pyrolysis of polymers, combustion of saccharides and biomass precursors are considered as the most promising electrode materials due to their ability to provide high energy density for batteries and high 4 power density for supercapacitors . In the present study, various samples of hard Carbon were synthesized through chemical acid activation of olive leaves as a largely available by-product of table olive and olive oil industries. The olive leaves derived hard carbon (labelled as OLDHC) materials are studied by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM) methods. The lithium/sodium intercalation capabilities and the charge storage ability and cycle life of the OLDHC were evaluated by cyclic voltammetry (CV) and charge/discharge galvanostatic cycles. The OLDHC electrode material for NIBs demonstrates promising performances with a high discharge capacity of 270 mAh/g at 1C between 0.02V and 3V. For LIBs, OLDHC anode material delivers a reversible discharge capacity of 500 mAh/g at 1C in the voltage range between 0.02V and 3V. The OLDHC also shows a high specific capacitance of 180 F/g at the scan rate of 1 mVs-1 and a remarkable capacity retention of 88% after 20000 cycles at 10 A/g. The good electrochemical performances indicate that this low cost material could be a promising candidate for dual functional batteries and supercapacitors.