On the Use of Soft Carbon and Propylene Carbonate-Based Electrolytes in Lithium-Ion Capacitors

The combined use of soft carbon (PeC) as anodicmaterial, and propylene carbonate (PC) as electrolyte solvent is a promising strategy for the realization of high performance lithium-ion capacitors (LIC). PeC electrodes display a capacity of around 80 mAhg(-1) during cycling carried out at 5C, which can be maintained for more than 10,000 cycles. This performance is higher than that displayed by most of the carbonaceous electrodes so far proposed for LIC. PC is known to be a safer electrolyte compared to mixtures of organic carbonates used so far in LIC, and therefore its use is beneficial for the realization of safer LIC. When a correct pre-lithiation process is applied, LICs based on PeC and PC display high performance in terms of capacity and cycling stability. When a current density of 10.6 mA/cm(2) (corresponding to 5.6 A/g) is applied to a LIC average energy and power of 21.7Wh kg(-1) and 4.1 kW kg(-1) (based to the total active material), respectively, were achieved. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.050208jes] All rights reserved.