High energy and power lithium-ion capacitor based on MnO-encased graphene spheres anode and hollow carbon nano-rods cathode

Abstract

High energy density, high power density and long lifespan lithium-ion capacitors (LICs) are increasing required in many electronic devices. However, the mismatch of capacity severely hinders the practical applications of LICs. Herein, hollow MnO@graphene nano-spheres (MnO@G-NS) are prepared by a high temperature calcination treatment of the hydrothermally-synthesized MnCO3-C spheres. The MnO@G-NS anode shows high capacity, outstanding rate performance (504 mAh g−1 at 3 A g−1), high initial coulombic efficiency (83.6%) and long lifespan cyclic stability. Meanwhile, S, N-codoped hollow carbon nano-rods (SNHCs) are obtained via a template-free calcination process. As the cathode, SNHCs displays high capacitiy, excellent rate capability (165 mAh g−1 at 10 A g−1) and ultralong cycling stability for 5000 cycles. Furthermore, MnO@G-NS//SNHCs is assembled by MnO@G-NS anode and SNHCs cathode, and delivers high energy density (126.7 Wh kg−1), high power density (5722 W kg−1) and long-term cycling stability for 10,000 cycles. Furthermore, a highly loaded (18 mg cm−2) LICs still delivered a high energy density of 111 Wh kg−1 at 999.4 W kg−1, and a higher power density of 5095.1 W kg−1 at 63.7 Wh kg−1 coupled with 81% capacity retention for 10,000 cycles at 10 A g−1, indicating a great application potential in LICs.