Engineering onion-like nanoporous CuCo₂O₄ hollow spheres derived from bimetal–organic frameworks for high-performance asymmetric supercapacitors

Abstract

An asymmetric supercapacitor fabricated using onion-like nanoporous CuCo2O4 hollow spheres exhibits an energy density of 48.75 W h kg−1 and a power density of 37.5 kW kg−1, which can compete with Ni–MH batteries.

Influence of Ga2O3, CuGa2O4 and Cu4O3 phases on the sodium-ion storage behaviour of CuO and its gallium composites

“…50 The Cu-2p scan also showed two strong photoelectron emissions de-convoluted at 935.4 eV and 955.3 eV, corresponding to the Cu-2p 3/2 and Cu-2p 1/2 electronic levels, respectively. 51,52 These are the characteristic peaks of Cu(II), and the Cu 2+ oxidized charge state in CuGa 2 O 4 exhibited a spin-orbit splitting energy separation of 19.9 eV which matched the previously reported values well. [51][52][53][54] The Ga-2p scan showed two peaks centred at 1118.18 eV and 1145.08 eV corresponding to Ga-2p 3/2 and Ga-2p 1/2 , respectively, as shown in Fig.…”

“…51,52 These are the characteristic peaks of Cu(II), and the Cu 2+ oxidized charge state in CuGa 2 O 4 exhibited a spin-orbit splitting energy separation of 19.9 eV which matched the previously reported values well. [51][52][53][54] The Ga-2p scan showed two peaks centred at 1118.18 eV and 1145.08 eV corresponding to Ga-2p 3/2 and Ga-2p 1/2 , respectively, as shown in Fig. 7c 51 , with an energy separation of 26.9 eV which matched the previously reported value well.…”

“…[56][57][58] The O-1s XPS scan is shown in Fig. 7e and has two de-convoluted peaks, one centered at 530.2 eV that corresponds to metal-oxygen bonding, 52,59 and the other one at 531.6 eV, corresponding to surface absorbed O 2 . 60 The slight shi of the O-1s peak towards higher binding energy than the reported values may be due to an interaction between the binary and ternary oxide phases present in the sample.…”

The controlled synthesis of complex hollow nanostructures and prospective applications

“…The authors supported that the superior electrochemical performance observed in these materials was possible due to the nanoporous nature of the shells, along with the high surface area available. In addition, the multi-shelled structure with nanometric width delivered an important synergistic effect between Cu and Co species in the spinel structure of the final material [142].…”

Multi-shelled Ni6MnO8 hollow microspheres for high-performance supercapacitors

“…For examples, Zhu et al prepared mesoporous NiCo 2 O 4 hollow spheres with PVP as a facile soft-template [26]. Ensafi et al designed onion-like CuCo 2 O 4 hollow microspheres with a diameter of about 1 μm by using bimetal-organic frameworks as a self-template [27]. The flexible multi-shelled soft templates such as vesicle are easily destroyed by changing parameters whereas the success for the conversion of single-shelled to multi-shelled hollow microspheres is limited for self-template method [28].…”