The Influence of Porous Co/CeO_1.88-Nitrogen-Doped Carbon Nanorods on the Specific Capacity of Li-O₂ Batteries

Abstract

Li-O 2 batteries are attracting considerable attention as a promising power source for electric vehicles as they have the highest theoretical energy density among reported rechargeable batteries. However, the low energy density and efficiency of Li-O 2 batteries still act as limiting factors in real cell implementations. This study proposes the cathode structure engineering strategy by tuning the thickness of a catalyst layer to enhance the Li-O 2 battery performance. The construction of the Li-O 2 battery with a thinner porous cathode leads less parasitic reactions at the solid electrolyte interface, maximization of the catalyst utilization, and facile transport of oxygen gas into the cathode. A remarkably high specific capacity of 33,009 mAh g −1 and the extended electrochemical stability for 75 cycles at a 1000 mAh g −1 limited capacity and 100 mA g −1 were achieved when using the porous Co/ CeO 1.88 -nitrogen-doped carbon nanorod cathode. Further, a high discharge capacity of 20,279 mAh g −1 was also achieved at a relatively higher current density of 300 mA g −1 . This work suggests the ideal cathode structure and the feasibility of the Co/CeO 1.88nitrogen-doped carbon nanorod as the cathode material, which can minimize the areal cathode catalyst loading and maximize the gravimetric energy density.

N-doped porous carbon nanofibers inlaid with hollow Co3O4 nanoparticles as an efficient bifunctional catalyst for rechargeable Li-O2 batteries

“…The metallic Co was finally oxidized in air at a mild temperature to form Co3O4 hollow nanoparticles inlaid in the CNFs (denoted as H-Co3O4-CNFs). In addition, N-doped carbon materials can be prepared by heating a composite of carbon materials and nitrogen-containing materials in an inert atmosphere [26,27]. Because nitrogen is contained in polyacrylonitrile (PAN), N-doped carbon fibers are expected to be formed in this process.…”

“…Furthermore, many studies have demonstrated that nitrogen-doped carbon materials can improve electrochemical properties owing to changes in the chemical and electronic properties of carbon-based materials, such as the formation of defects and functional groups derived from heteroatom doping [24][25][26][27]. Yan et al [24] used DFT calculations to show that N-doping could boost the adsorption of oxygen atoms and reduce the energy barrier of oxygen molecular dissociation from 2.39 to 1.20 eV, resulting in better catalytic activity toward ORR and OER.…”

2D Co-doped MnCr2O4 nanosheets as efficient bifunctional cathode materials for long-life Li–O2 batteries

“…Meanwhile, the MnCoCrO electrode has higher redox peak current and peak area, which indicates that MnCoCrO can generate more Li 2 O 2 during the discharge process; in other words, the MnCoCrO electrode has a higher discharge capacity, coinciding with the full charge-discharge curve. 50,51 In order to avoid overcharge at low current density, the voltage window is deliberately set at 2.0-4.3 V to test the full charge-discharge performance. Clearly, MnCoCrO cathodes exhibit higher discharge and charge capacities compared with MnCrO and MnCoO electrodes.…”

Engineering Metal Alloy Nanocrystals Anchored on N‐Doped Nanoporous Carbon for Li‐O2 Batteries

“…Due to the excellent electrical conductivity, stable structure, and inexpensive cost, carbon-based materials have recently been widely applied in the LOBs cathodes. [20][21][22][23] Thereinto, the N-doped materials, such as carbon nanotubes, graphene, and nanofibers, are attracting particular interest as the oxygen catalysts for LOBs because the introduction of N can tune the charge and spin distribution of adjacent C atoms due to the higher electronegativity of N than C. [24][25][26][27][28][29] However, most metalfree carbon-based catalysts' performance is still much inferior to precious metal catalysts; fortunately, the introduction of the transition metal nanoparticles supported on the porous Ndoped carbon has been proved as an effective alternative approach for improving the performance. It has been reported that the synergy between the metals and the N-doped carbon substrate can effectively modify the local electronic structure, thereby optimizing the intermediate adsorption and resulting in a superior activity.…”

“…Due to the excellent electrical conductivity, stable structure, and inexpensive cost, carbon‐based materials have recently been widely applied in the LOBs cathodes [20–23] . Thereinto, the N‐doped materials, such as carbon nanotubes, graphene, and nanofibers, are attracting particular interest as the oxygen catalysts for LOBs because the introduction of N can tune the charge and spin distribution of adjacent C atoms due to the higher electronegativity of N than C [24–29] .…”