A high-performance hard carbon for Li-ion batteries and supercapacitors application

A hard carbon (HC) prepared from phenolic resins is investigated as a potential electrode material for power Li-ion batteries and hybrid supercapacitors. The electrochemical test results indicate that the HC is capable of delivering a capacity of 526 mAh g(-1) (about 40% greater than graphite) with an initial coulombic efficiency of 80%. The constructed Li(Ni1/3Co1/3Mn1/3)O-2/HC full cells shows superior power capabilities, retaining 90% of reversible capacity at a discharge rate as high as 30 C. That is equivalent to a specific energy of 98 Wh kg(-1) at a power of 3000 W kg(-1). When combined with an activated carbon (AC), the constructed AC/HC hybrid capacitor exhibits a specific capacitance of 21.5 F g(-1) or energy density of 22.6 Wh kg(-1) (considering the weight of all components of the full cell) at a current of 100 mA g(-1). At a power of 480 W kg(-1), it delivers an energy density of 20.8 Wh kg(-1), which is twice that of a conventional AC/AC supercapacitor. The feature of high energy and power capabilities makes HC materials promising candidates as electrodes for energy storage and conversion application. (C) 2012 Elsevier B.V. All rights reserved.