Effect of Substitutional and Interstitial Boron-Doped NiCo₂S₄ on the Electronic Structure and Surface Adsorption: High Rate and Long-Term Stability

Abstract

The effect of substitutional and interstitial doping on the electronic structure and surface adsorption plays an important role in tuning physical and chemical properties. Herein, boron-doped NiCo2S4 (B-NiCo2S4) was designed and prepared for high rate and long-term stability supercapacitors, considering the substitutional and interstitial boron (Bsub and Bint) doping due to similar atomic size. The low conductivity and slow reaction kinetics of NiCo2S4 hampered its rate performance and weak cycle stability for energy storage devices. After boron doping, B-NiCo2S4 can promote electron transfer to improve rate performance and increase surface adsorption energy to capture the electrolyte ion due to electronegativity difference during the charge/discharge process. Furthermore, the contribution of Bsub and Bint doping modes can be elucidated by density functional theory calculations. The density of states of B-NiCo2S4 (26.7 eV–1) was much higher than that of NiCo2S4 (6.2 eV–1) near the Fermi level resulting from Bsub doping. The doping-induced charge transfer was enhanced by adjusting the position of the Fermi level. Bint doping redistributed the surface charge, resulting in increased OH– adsorption and then improved Faradaic reaction kinetics in alkaline electrolyte. This research strategy implements the research of synergistic promotion of theoretical prediction and experimental verification very well.

Porous Carbon Framework with B-Doped NiCo2O4 Nanoclusters for Enhancing the Performance of Carbon Fiber-Based Flexible Supercapacitors

“…As shown in Figure c, O exhibits a characteristic peak at the binding energy of 529.58 eV, representing the M-O bond formed by Co and Ni with O. After B doping, the peak intensity of the original Co–O and Ni–O decreases due to the substitution of a small amount of O by boron atoms to form Co–B and Ni–B bonds Figure d shows the high-resolution XPS spectra of Ni 2p, showing the spin orbitals of Ni 2p 1/2 (binding energies: 874.86 and 872.37 eV) and Ni 2p 3/2 (binding energies: 855.22 and 854.74 eV), respectively .…”

Oxygen-Defect-Rich B-ZnCo2O4-x Nanocatalyst for Efficient Conversion Kinetics of Lithium–Sulfur Batteries

“…It can be found from Figure e that the edge of B-ZnCo 2 O 4‑x shows disorderliness due to the doping effect. The defects caused by boron doping may enhance the irregularity of ZnCo 2 O 4 and expose more polysulfide adsorption sites. In the HRTEM image of B-ZnCo 2 O 4‑x (Figure S2), the main lattice fringes of 0.277 and 0.156 nm are well indexed as the (220) and (511) planes of ZnCo 2 O 4 , respectively .…”

High-performance flexible solid-state asymmetric supercapacitor with NiCo2S4 as a cathode and a MXene-reduced graphene oxide sponge as an anode

“…The splitting energies of both pairs were 15 and 15.55 eV, respectively, which indicated the presence of Co(II) as well as Co(III). 19,47 The S 2p spectrum (Fig. 4c) is tted with two main peaks at 162.05 eV (S 2p 3/2 ), 163.3 eV (S 2p 1/2 ), and one shakeup satellite peak at 168.6 eV, indicating the presence of S 2− .…”

“…7d (also see Table S2 †). 11,22,24,26,35,36,47,[49][50][51] The exibility of the as-prepared device was also tested by altering its angle to 0°, 90°, 180°, and twist forms. The CV (Fig.…”