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The Li-ion capacitor (LIC) is composed of a lithium-doped carbon anode and an activated carbon cathode, which is a half Li-ion battery (LIB) and a half electrochemical double-layer capacitor (EDLC). LICs can achieve much more energy density than EDLC without sacrificing the high power performance advantage of capacitors over batteries. LIC pouch cells were assembled using activated carbon (AC) cathode and hard carbon (HC) + stabilized lithium metal power (SLMP ® ) anode. Different cathode configurations, various SLMP loadings on HC anode, and two types of separators were investigated to achieve the optimal electrochemical performance of the LIC. Firstly, the cathode binders study suggests that the PTFE binder offers improved energy and power performances for LIC in comparison to PVDF. Secondly, the mass ratio of SLMP to HC is at 1:7 to obtain the optimized electrochemical performance for LIC among all the various studied mass ratios between lithium loading amounts and active anode material. Finally, compared to the separator Celgard PP 3501, cellulose based TF40-30 is proven to be a preferred separator for LIC. IntroductionPeople are always pursuing more efficient energy storage devices which can provide high energy density, good power performance and long cycle life. The electrochemical double-layer capacitor (EDLC) contains two symmetrical activated carbon electrodes with high surface area and porous structure. Although the EDLC has the characteristics of high power and long cycle life, the energy density of an EDLC is less than 10% of that of a Li-ion battery (LIB), which restricts its application in the field of hybrid electric vehicles (HEVs), electric vehicles (EVs) and other large-scale energy storage systems. Therefore, in recent years considerable research has been focused on the development of a high energy density EDLC. Among all the energy storage systems that have been investigated and developed in the last few years, Li-ion Capacitors (LICs) have emerged to be one of the most promising because LICs achieve higher energy density than conventional EDLCs, and better power performance than LIBs as well being capable of long cycle life. LICs contain a pre-lithiated LIB anode electrode and an EDLC cathode electrode 1-3 . Extensive research has been done to optimize the electrochemical performance of the LICs 4-19 . Recently, Xu et al. 20 reported the effect of the electronic spatial extents (ESE) of ions for overpotential of Li-ion capacitors. Zhang et al. 21 studied