The effect of carbon–polyaniline hybrid coating on high-temperature electrochemical performance of perovskite-type oxide LaFeO₃ for MH–Ni batteries

Abstract

An efficient carbon-polyaniline (PANI)-coated method was applied for perovskite-type oxide LaFeO3 to enhance its high-temperature electrochemical performance. Transmission electron microscopy (TEM) results reveal that LaFeO3 particles are evenly coated with carbon and PANI hybrid layers after carbon-PANI treatment. The carbon layers prevent the nanosized LaFeO3 particles from aggregation and allow the electrolyte to penetrate in every direction inside the particles. The PANI layers also enhance the electrocatalytic activity, facilitating hydrogen protons transferring from the electrolyte to the electrode interface. The cooperation of carbon and PANI hybrid layers results in a significant enhancement of the electrochemical performance at high temperatures. At an elevated temperature (60 °C), the maximum discharge capacity of the LaFeO3 electrodes remarkably increases from 231 mA h g(-1) to 402 mA h g(-1) and the high rate dischargeability at a discharge current density of 1500 mA g(-1) (HRD1500) increases from 22.7% to 44.3%. Moreover, the hybrid layers mitigate the corrosion of LaFeO3 electrodes by reducing the loss of active materials in the alkaline electrolyte, leading to increase in the capacity retention rate from 67.1% to 77.6% after 100 cycles (S100).

Heterogeneous photo-Fenton degradation of organics using highly efficient Cu-doped LaFeO3 under visible light

“…As shown in Fig indicating that the fabricated samples were well crystallized with orthorhombic structure (JCPDS No. 37-1493) [52,53]. No crystalline Cu peaks were observed and the single…”

Review: on rare-earth perovskite-type negative electrodes in nickel–hydride (Ni/H) secondary batteries

“…Accordingly, the improvement of charge transfer at the [66] electrode/electrolyte interface and of the hydrogen mass transportation are key factors to achieve a better performance in hydrogen batteries. In this sense, recent studies have proposed nanosized RE-perovskite oxide particles for the production of negative electrodes on the basis that nanomaterials with high surface area could maximize the surface activity [64,65]. As a result, nanosized RE-perovskite-type oxides should improve the reaction kinetics of electrode materials, and afford a shorter distance for ionic mass and charge transportation.…”

“…These reagents are mixed in distilled water and heated until the excess free water evaporates. Subsequently, the resulting viscous liquid is auto-ignited by putting it in a preheated plate at a temperature around 673 K. Subsequently the as-burnt powder is calcined at a temperature typically around 1200 K for 3 to 5 h. This method has been reported in numerous studies involving RE-perovskite-type oxides for applications in Ni/MH batteries [27,59,64,65]. For instance, Deng et al [59] prepared RE-perovskite-type oxides to built-up electrodes for Ni/MH cells using the combustion method.…”

“…For instance, it must help to avoid the aggregation of particles, be supportive in favor of hydrogen transfer, and provide protection against the alkaline electrolyte, especially at elevated temperatures. Recently, LaFeO 3 particles have been evenly coated with carbon and polyaniline (PANI) hybrid layers after carbon-PANI treatment [65]. The carbon layers prevent the nano-sized LaFeO 3 particles from aggregation.…”

Electrochemical performance of the rare-earth perovskite-type oxide La0.6Sr0.4Co0.2Fe0.8O3 as negative electrode material for Ni/oxide rechargeable batteries

“…In addition to the conductivity issues, the hydrogen diffusion coefficient presents low values when compared with those of intermetallic compounds. Recently, various solutions have been proposed to improve these weak points [16][17][18]. One of the attempts for improving the electrochemical performance of the oxide electrodes was the introduction of dopant elements within the perovskite structure.…”