Morphological and Structural Evolution of MnO@C Anode and Its Application in Lithium-Ion Capacitors

Lithium-ion capacitors (LICs) have captured a lot of attention due to their ability to meld the energy of lithium-ion batteries (LIBs) with the power of supercapacitors (SCs). In this work, high performance LICs were fabricated by using core–shell MnO@C as the anode and trisodium citrate-derived carbon (TSC) as the cathode. Half coin cells with MnO@C anode can deliver a reversible specific capacity of 973.14 mAh g–1 at 0.25 A g–1 after 200 cycles. The reversible morphological and structural evolution of MnO@C anode had been unveiled by ex-situ characterizations. Electrode kinetics had also been studied by in situ EIS. Asymmetric LICs with a mass ratio of 1:5 (anode to cathode) have a working voltage of 3.9 V, a maximum energy density of 235 Wh kg–1 at 120 W kg–1, and a maximum power density of 25000 W kg–1 at 61 Wh kg–1. It can maintain 85.69% of its initial capacity after 10000 cycles. Therefore, the asymmetric MnO@C//TSC LIC is demonstrated as a high performance device for energy storage.