Rui Niu’s research while affiliated with Ningxia University and other places

In this paper, TiO2 nanoparticles (NPs) were exploited with carbon nanotube (CNTs) to form a composite electrode (TiO2/CNTs) for capacitive deionization (CDI). The phase morphology, crystal and electronic structure were characterized by scanning electron microscopy, Transmittance electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The electrochemical behavior was carried out by cyclic voltammetry. Furthermore, the desalination performances of TiO2/CNTs composite electrode were investigated at different electrical voltages and ionic strengthen in a batch mode operation. The results demonstrated that the TiO2/CNTs electrode prepared from 1 wt% TiO2 NPs (TiO2/CNTs-1) exhibits the best results compared to other electrodes having 2 and 5 wt% TiO2 NPs. Remarkably, the best electrode showed high specific capacitance (122 F/g) at 1 mV/s in 1 M KCl solutions and excellent electrosorptive capacity (4 mg/g) predicted from Langmuir isotherm which is nearly twice higher than that of pristine CNTs electrode. Moreover, the electrosorption follows the pseudo first adsorption kinetics and the proposed electrode shows interesting recyclability and easy full regeneration.

The amount of ions stored within the electrochemical double layer is dominantly determined by the surface area of porous electrode. High surface area indicates high capacitance. However, this is not the case when the pore is extremely small, ∼less than 1 nm. To observe this phenomenon, we have carried out an experiment by comparatively investigating the electrochemical performance of activated carbon (AC) and sulfuric acid treated AC (SAC). The results show that the electrochemical performance of SAC involving the specific capacitance, rate capability and cycling stability is significantly increased as compared to pristine AC. These are attributed to the improved porosity by differentiating the respective contributions of electrochemical double layer capacity and pseudo-capacity from SAC and AC, respectively.

Capacitive deionization (CDI) is a promising desalination technique that gains more and more attentions worldwide in recent years due to its high efficiency and feasibility. In this work, the sulfuric acid functionalized activated carbon (FAC) is proposed as electrode for CDI. By compared to pristine AC, FAC electrode shows an improved microspores volume from 0.17 to 0.22 m3 g-1 and therefore a high electrosorption capacity of 3.54 mg g-1 as well as a charge efficiency of 0.21. Furthermore, the FAC electrode follows the Langmuir isotherm, indicating the monolayer adsorption. Besides, the pseudo-first-order can describe the adsorption kinetics of FAC electrode as compared to other kinetics models. Additionally, the FAC electrode can be regenerated very well.

In this work, the sulfonated reduced graphene oxide (SRGO) was synthesized and proposed as an enhanced anode material for lithium ion battery (LIB). The result shows that the SRGO has an improved battery performance (i.e., ∼341.7 mAh/g and ∼ 190.6 mAh/g corresponds to SRGO and RGO at the 100th cycle with a current density of 200 mA/g) and superior cycling stability compared with pristine reduced graphene oxide (RGO). These are attributed to the improved specific surface area (448.35 m2/g) and conductivity (2.5 × 10-4S/m). Further, the SRGO exhibits good rate capability and excellent energy density at various current densities ranging from 50 mAh/g to 2000 mAh/g, suggesting that SRGO could be a promising anode material for high capacity LIB.