Li-ion capacitor based on activated rice husk derived porous carbon with improved electrochemical performance

We report the fabrication of a high energy-power density Li-ion hybrid supercapacitor (Li-HSC) using rice husk derived activated porous carbon as cathode and insertion type Li4Ti5O12 (LTO) as anode. Nanoporous carbon chemically activated with KOH (RHDPC-KOH) and H3PO4 (RHDPC-H3PO4) exhibited high surface area and improved porosity characteristics. With optimized electrode mass loading, the fabricated Li-HSC exhibited excellent electrochemical properties with a maximum energy density of similar to 57 Wh kg similar to 1 and similar to 37Wh kg(-1) for LTO/RHDPC-KOH and LTO/RHDPC-H3PO4 configuration respectively. The obtained energy density of 45 Wh kg(-1) for RHDPC-KOH -based Li-HSC, even at a high power density of similar to 4.3 kW kg(-1), is far superior to several porous carbon-based Li-ion capacitors reported. Furthermore, the device showed excellent cyclability with capacity retention of similar to 92% of initial capacity even after 2000 cycles, at high current density of 2 Ag-1. (C) 2016 Elsevier Ltd. All rights reserved.