Efficiency of 3D‐Ordered Macroporous La_0.6Sr_0.4Co_0.2Fe_0.8O₃ as an Electrocatalyst for Aprotic Li‐O₂ Batteries

Abstract

Li‐O 2 batteries (LOBs) with an extremely high theoretical energy density have been reported to be the most promising candidates for future electric storage systems. Porous catalysts can be beneficial for LOBs. Herein, 3D‐ordered macroporous La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 perovskite oxides (3D‐LSCF) are applied as cathode catalysts in LOBs. With a high Brunauer‐Emmett‐Teller surface area (21.8 m 2 g −1 ) and unique honeycomb‐like macroporous structure, the 3D‐LSCF catalysts possess a much higher efficiency than La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) nanoparticles. The unique 3D‐ordered macropores play a significant role in the product deposition as well as oxygen and electrolyte transmission, which are crucial for the discharge‐charge processes of LOBs.

Bifunctional electrochemical properties of La0.8Sr0.2Co0.8M0.2O3−δ(M = Ni, Fe, Mn, and Cu): efficient elemental doping based on a structural and pH-dependent study

“…[8][9][10] One way to improve the OER/ORR of perovskite oxides is to increase their specific surface area and porosity of the catalysts, which have been reported to be beneficial for exposing more accessible active sites and facilitating the mass transfer and electron transfer during the OER/ORR processes. 11,12 However, the morphology optimization is difficult to break through the limitation of material's intrinsic properties. Thus, we explored another efficient approach that is to optimize the intrinsic structures of the perovskite oxides by elemental doping or nonstoichiometric substitution.…”

Wrinkled Perovskite La0.9Mn0.6Ni0.4O3−δ Nanofibers as Highly Efficient Electrocatalyst for Rechargeable Li−O2 Batteries

“…Compared with the LMN NPs, the LMN NFs exhibit evidently higher peak current densities, especially at 3.78 V, indicative of higher OER electrocatalytic properties of the LMN NFs. The improved electrocatalytic ability is mainly because the wrinkles‐like surface with porous structure has more active sites to catalyze the formation and decomposition of Li 2 O 2 . The special morphology linked with the discharge/charge process of Li−O 2 battery will be deeply discussed in later section.…”

“…The improved electrocatalytic ability is mainly because the wrinkles-like surface with porous structure has more active sites to catalyze the formation and decomposition of Li 2 O 2 . [27,28] The special morphology linked with the discharge/charge process of LiÀ O 2 battery will be deeply discussed in later section. Figure 4c and d show the capacities of the LiÀ O 2 batteries with voltage window of 2.2-4.5 V. Obviously, with the increase of current density, the discharge capacities of both batteries with the LMN NFs and LMN NPs are decreased and the overpotentials increase.…”

“…However, perovskite oxides prepared by the conventional sol‐gel method only have low catalytic activity due to their extreme low electronic conductivity and small specific surface areas. A series of studies have reported that Li−O 2 batteries using perovskite catalysts with special morphology, such as La 0.6 Sr 0.4 Co 0.8 Mn 0.2 O 3 nanofibers loaded with RuO 2 nanosheets, 3D‐Ordered macroporous La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 and hierarchical porous La 0.5 Sr 0.5 CoO 3− x nanotubes, could effectively improve the specific capacity and cycling stability by decreasing the discharge/charge overpotentials. Porous nanostructured perovskites could supply more catalytic sites to catalyze the formation and decomposition of Li 2 O 2 and special nanostructure to store the insulated discharge products.…”

Superassembly of Porous Fetet(NiFe)octO Frameworks with Stable Octahedron and Multistage Structure for Superior Lithium–Oxygen Batteries

“…[ 35 ] La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 perovskite oxides were also constructed by Chi et al, which guaranteed 198 cycles at a current of 400 mA g −1 . [ 36 ] Inspired by the state‐of‐the‐art molecular orbital theory [ 37 ] and d‐band center model [ 38 ] in the perovskite catalysts category which describe the internal relation between catalyst–reactant bond and the antibonding occupancy, spinel oxides with optimized structure have been attracted as a very popular catalyst which would promise a significant performance for LOBs, such as Co 3 O 4 /Ni–Co 3 O 4 nanowires, [ 39 ] MnCo 2 O 4 microspheres, [ 40 ] CoFe 2 O 4 hollow nanospheres, [ 41 ] 3D foam‐like NiCo 2 O 4 [ 42 ] and so on. However, previous works rarely reported spinel oxides focusing on the metal cations occupying on the octahedral and tetrahedral sites, determining the electrocatalytic performance in terms of the established activity descriptors (e.g., occupancy, d electrons, metal–oxygen covalency and O‐p band center) in metal oxide based catalysts.…”