While supercapacitors can deliver high electrical power, their low energy density limits their application. Here, we designed and fabricated a facile asymmetric supercapacitor (ASC) with excellent electrochemical performance, where MnO 2 nanoflowers (NFs) and La 2 O 3 nanospheres (NSs) were successfully electrodeposited onto carbon paper as work electrodes in an aqueous 0.5 M Na 2 SO 4 electrolyte. Such nanostructures endow the electrodes with short electrons, ion diffusion paths, and abundant charge adsorption sites. The assembled MnO 2 NF//La 2 O 3 NS asymmetric cell presents a gravimetric energy density of 80.56 Wh kg −1 , a volumetric energy density of 0.74 mWh cm −3 at 35.71 mA cm −3 , and excellent cycle performance. Moreover, a packaged device displays a superior energy density of 0.49 mWh cm −3 with a power density of 94.29 mW cm −3 . The satisfactory improvement in performance mainly stems from the homogeneous nanostructured architecture and an extended workable potential region of 0− 2.0 V. The resulting supercapacitors could have great potential for designing high energy and power density devices as effective power sources.

Lanthanum-based materials have attained increasing attention because of their high adsorption property of phosphate ions and their environmental harmlessness. However, challenges still remain to improve the phosphate adsorption capacity and find suitable materials for the lanthanum attachment substrate. Nickel foam with characteristics such as excellent uniformity, large specific surface area, high porosity, and low conductivity is considered to be the alternative for the preparation of lanthanum-based adsorption materials. An efficient adsorbent foamed nickel-based La (OH) 3 nanowire was first prepared with a facile one-step electrodeposition method. The batch static adsorption tests of simulative wastewater (e.g., coexisting ions and solution pH values) were employed to investigate the phosphate adsorption kinetics and solution matrix effects of the materials. The results indicate that the composite exhibits fast adsorption kinetics within 30 min and high selectivity to phosphate under interference from competing ions. The pH value of wastewater has great influence on the absorption of phosphate, and optimal adsorption capacity can be achieved over a pH 4−6 range. Various findings revealed that the adsorption behavior of lanthanum hydroxide/foamed nickel [La(OH) 3 /Ni] followed inner-sphere adsorption through the ligand-exchange mechanism. The prepared material is expected to be an enormous potential candidate for the removal of low-concentration phosphorus from effluents.

The La@Ni/CG double hydroxides (LDHs) were obtained by a electrodeposition method. The synergistic effect of the active species in La@Ni/CG, which can be attributed to the improved electrochemical performance of the composite.