Abstract
To meet practical application requirements, high specific energy and specific power and excellent cyclability are highly desired. Herein, we design and synthesize fine CuCo
2
O
4
nanoparticles wrapped in a conductive rGO aerogel network as a robust conductive anode for Li-ion capacitors (LICs). The nanostructure of the resulting CuCo
2
O
4
/rGO composite provides a high capacity of 1285 mA h g
−1
at a small current density of 0.1 A g
−1
. Moreover, the conductive anode was combined with an activated carbon (AC) cathode (denoted as CuCo
2
O
4
/rGO//AC) to construct high-performance LICs. The as-prepared device (CuCo
2
O
4
/rGO//AC LIC) exhibits capacitance of 49.5 F g
−1
at 1 A g
−1
and retained capacitance of 34.0 F g
−1
when the current density increased to 4 A g
−1
, demonstrating outstanding rate performance. Excitingly, our fabricated CuCo
2
O
4
/rGO//AC LIC exhibits ultra-high specific energy and specific power (396 W h kg
−1
/8 kW kg
−1
) with excellent cyclability (∼100% retention after 16 000 cycles) for the first time. We demonstrate that a single LIC cell could light a blue LED with sufficient illumination for 100 s, opening the way to possible realistic applications. Additionally, based on the synergistic effect of the conductive rGO aerogel matrix and the downsized CuCo
2
O
4
particles of the CuCo
2
O
4
/rGO anode, the superior electrochemical performance was attributable to increased conductivity and structural integrity during Li
+
insertion/extraction.