High-capacity MnCo2O4 supported by reduced graphene oxide as an anode for lithium-ion capacitors

Abstract

In order to construct lithium-ion capacitors (LICs) possessing superior performance, a two-step solvothermal method was adopted to prepare high-capacity MnCo2O4 supported by reduced graphene oxide (rGO). MnCo2O4 particles were formed at the first step and then at the second step they were coated onto the surface of rGO sheets. The introduction of rGO boosted the electronic conductivity and the specific surface area. Such synthesized MnCo2O4/rGO composite was employed as an anode of lithium-ion batteries. An ultrahigh initial discharge capacity (1657 mAh g‒1, 0.1 A g‒1) was achieved. And after this anode was repetitively charged/discharged at 0.2 A g‒1 for 100 cycles, a high reversible capacity (791 mAh g‒1) was also presented. A LIC was constructed by using this superior-performance MnCo2O4/rGO composite acting as an anode coupled with an activated carbon (AC) cathode. The maximum specific energy and specific power of the MnCo2O4/rGO//AC LIC reached 78.8 Wh kg‒1 and 3.0 kWh kg‒1, respectively. Moreover, for this LIC, at the end of the 1000th cycle, the capacity retention ratio was 76.9%.