LAUSR

Abstract The mediocre capacitive performance of carbon cathode has seriously hampered the advancement of lithium ion capacitors (LICs). The guideline for high-performance capacitive carbon cathode is still lacking. In this study, the desired microstructure of carbon cathode that suitable for LiPF6-contained electrolyte is calculated by using density functional theory. Results suggest that only the pore sizes more than 2.18 nm can accommodate the solvated P F 6 - ions. Experimental results confirm that the capacitive performance of the synthesized activated polyaniline-derived carbon (APDC) can be significantly promoted as the pore size was more than 2 nm. Especially, the APDC-700-based electrode demonstrates outstanding electrochemical performance with high capacitance (247 F g-1 at 0.1 A g-1) and good rate capability (156 F g-1 at 10 A g-1), owing to the appropriate pore size and high N content in carbon matrix. The APDC-700-based LIC device can deliver an ultra-high energy density of 300.3 Wh kg-1 at 318 W kg-1, as well as good cycling stability over 10 000 cycles. This well-designed work will be conducive to deeply understand the performance improvement of capacitive carbon cathode in LiPF6 electrolyte and provides guidelines for designing advanced LIC devices.