Fabrication of High Energy Li-Ion Capacitors from Orange Peel Derived Porous Carbon

Activated carbon (AC) with high surface area (1,901 m(2) g(-1)) is synthesized from bio-waste orange (Citrus sinensis) peel for fabrication of high specific energy lithium ion capacitors (LICs). The composition, structure and electrochemical properties of orange peel derived AC (OP-AC) are characterized by elemental analyzer, field emission-scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammogram, charge-discharge and impedance studies. Fabricated LIC using the high surface area OP-AC with pre-lithiated graphite (LiC6) delivered specific energy of similar to 106 Wh kg(-1). In addition, LIC configuration with Li4Ti5O12 was also fabricated and observed to be capable of delivering the specific energy of similar to 35 Wh kg(-1). Symmetric configuration of OP-AC with aqueous and organic solutions was also made for comparison purpose. A systematic improvement from the specific energy of similar to 7 to 106 Wh kg(-1) is noted from aqueous to LIC assembly. The findings open up the possibility of developing high specific energy LICs from abundant, low-cost, sustainable biomass waste.