Electrochemical Charge and Discharge Performance of Perovskite-Type Oxide La_1−x Na _x FeO₃ (x = 0–0.8) in Alkaline Solution

Abstract

LaFeO3 as a new negative electrode material for nickel-hydrogen batteries used as energy storage has the advantages of high capacity, advanced temperature resistance, and low cost. However, its conductivity and dynamic performance are poor, seriously hindering its applications. In light of increasing concentration of oxygen vacancies and improving conductivity after replacing A-site elements of the material, here we synthesize low-priced Na doping LaFeO3 oxides, La1−x Na x FeO3 (x = 0–0.8), as the negative electrode by a solid-state reaction method. Studies show that doping Na can reduce particle aggregation, thus helping to increase the surface area of LaFeO3. Therefore, its discharge capacity remarkably increases to 356.7 mAh g–1 (x = 0.6) from 178.8 mAh g–1 (x = 0) at 60 °C, which also maintains 73.4% after 100 cycles for La0.4Na0.6FeO3, elevated by 55.1% compared to LaFeO3. In addition, the high rate discharge ability of an La0.4Na0.6FeO3 electrode at a discharge current density of 1500 mA g–1 reaches 30.7% in contrast to 11.2% for undoped LaFeO3. As such, the La0.4Na0.6FeO3 material with superior cycling capacity is proven to be a more promising electrochemical hydrogen storage electrode compared to LaFeO3, which greatly increases the practical application value of the material.

Surface modification of perovskite‐type oxide LaFeO3 with electroless nickel deposition for application in MH‐Ni batteries

“…The highest value is achieved using the electrode 3# with the longest coating time. These data suggest that the nickel plating could improve the HRD performance of the LFO electrode material more effectively compared to other methods, such as ionic doping, [19][20][21][22] carbon cladding modification, [27][28][29] composite with rGO, [30] and so on. However, the HRD value of the nickel-coated LFO alloy is lower than that of the LaNi 5 type alloy, and therefore further improvement in the performance of the surface modified LFO alloy is required in the future work.…”

“…[18] Further studies have revealed that the conductivity of this type of electrode could be significantly affected by the doping of different rare earth elements (or alkaline earth metals) and transition group metals. [19][20][21] Ren et al [22] reported that by increasing the amount of the doped ions, the discharge capacity of the battery with La 1-x Na x FeO 3 (x = 0-0.8) oxide electrodes at 60 • C was improved from 178.8 to 356.7 mAhg −1 , which was higher than that of battery with commercial AB 5 hydrogen storage electrode at room temperature. Deng et al [23,24] developed the La 1-x Sr x FeO 3 oxide electrodes (x = 0.2, 0.4) using a stearic acid combustion method and found that the initial discharge capacity of the as-fabricated battery was significantly improved by the addition of Sr element in the A-site cation, which can strikingly improve the conductivity of the electrode.…”