Hybrid system of nickel–cobalt hydroxide on carbonised natural cellulose materials for supercapacitors

Abstract

Advanced carbon materials formed from abundant biomass are an exciting and promising class for energy devices due to the clear advantages of low cost, sustainability and good physical and electrochemical properties. However, these materials typically do not compete well with their metal functionalised counterparts. In this work, we demonstrate that xCo(OH) 2 -(1−x)Ni(OH) 2 with various Ni:Co ratios can be deposited onto biomass-derived carbon to make a hybrid inorganic-carbon electrode with tuneable physical features and electrochemical performance. These features were tuned by adjusting the Ni:Co ratio within precursor solutions. The electrodes had shown a capacitance ranging from 780.7 to 2041 F g −1 , which is very close to the theoretical value for Ni(OH) 2 (2365 F g −1 ). A hypothesis is presented to help explain this performance for a modified, biomass-derived carbon electrode.

Intrinsic Oxidase-like Nanoenzyme Co4S3/Co(OH)2 Hybrid Nanotubes with Broad-Spectrum Antibacterial Activity

“…As shown in Figure 3, when treating the precursor of Co-pH-3 with 900 mg of Na 2 S the diameter of the nanotubes (∼70 nm) is the thinnest. Moreover, in Figure 42 The difference between the peaks is 15.7 eV, which is the characteristic of Co(OH) 2 . 42 The binding energies at about 796.7 (Co 2p1/2) and 780.8 eV (2p3/2) with two low intensity satellites at about 802.7 and 785.6 eV can be fitted to Co 4 S 3 .…”

“…Moreover, in Figure 42 The difference between the peaks is 15.7 eV, which is the characteristic of Co(OH) 2 . 42 The binding energies at about 796.7 (Co 2p1/2) and 780.8 eV (2p3/2) with two low intensity satellites at about 802.7 and 785.6 eV can be fitted to Co 4 S 3 . 26,43 The coexistence of Co 2+ and Co 3+ and the bond of Co 4 S 3 /Co(OH) 2 can be affirmed to the gap between Co 2p1/ 2 and 2p3/2.…”

“…The full scan spectrum (Figure A) indicates that Co, S, and O coexist in the materials. As shown in Figure B, the Co 2p spectra shows peaks at 799.2 eV (2p 3/2) and 783.5 eV (2p1/2) with two satellites located at 787.2 and 803.3 eV, which are the characteristic binding energy of a Co 2+ of Co­(OH) 2 . The difference between the peaks is 15.7 eV, which is the characteristic of Co­(OH) 2 .…”

“…As shown in Figure B, the Co 2p spectra shows peaks at 799.2 eV (2p 3/2) and 783.5 eV (2p1/2) with two satellites located at 787.2 and 803.3 eV, which are the characteristic binding energy of a Co 2+ of Co­(OH) 2 . The difference between the peaks is 15.7 eV, which is the characteristic of Co­(OH) 2 . The binding energies at about 796.7 (Co 2p1/2) and 780.8 eV (2p3/2) with two low intensity satellites at about 802.7 and 785.6 eV can be fitted to Co 4 S 3 . , The coexistence of Co 2+ and Co 3+ and the bond of Co 4 S 3 /Co­(OH) 2 can be affirmed to the gap between Co 2p1/2 and 2p3/2 .…”

A study of multilayered electrochromic platings based on nickel and cobalt hydroxides

“…It is known that cobalt compounds have a positive effect on the properties of nickel hydroxide in accumulators [23], supercapacitors [24] and nickel-based electrochromic devices [14,25]. Activation of nickel oxide electrode with cobalt additive improves the utilization coefficient of active material in alkaline accumulators by 10-15 %.…”