An Effective Integrated Design for Enhanced Cathodes of Ni Foam-Supported Pt/Carbon Nanotubes for Li-O₂ Batteries

Abstract

Designing an effective microstructural cathode combined with a highly efficient catalyst is essential for improving the electrochemical performance of Li-O2 batteries (LOBs), especially for long-term cycling. We present a nickel foam-supported composite of Pt nanoparticles (NPs) coated on self-standing carbon nanotubes (CNTs) as a binder-free cathode for LOBs. The assembled LOBs can afford excellent electrochemical performance with a reversible capacity of 4050 mAh/g tested at 20 mA/g and superior cyclability for 80 cycles with a limited capacity of 1500 mAh/g achieved at a high current density of 400 mA/g. The capacity corresponds to a high energy density of ∼3000 Wh/kg. The improved performance should be attributed to the excellent catalytic activity of highly dispersed Pt NPs, facile electron transport via loose CNTs connected to the nickel foam current collector, and fast O2 diffusion through the porous Pt/CNTs networks. In addition, some new insights from impedance analysis have been proposed to explain the enhanced mechanism of LOBs.

A Review of Carbon-Composited Materials as Air-Electrode Bifunctional Electrocatalysts for Metal–Air Batteries

“…Based on initial charge-discharge behaviors, a comparison of ORR and OER showed that PtRu/C possessed lower overpotentials for charging and discharging than PtPd/C and PtIr/C, in which the capacity followed an order: PtRu/C (~ 346 mAh g −1 ) > PtPd/C (~ 153 mAh g −1 ) > PdIr/C (~ 135 mAh g −1 ). Table 2 shows the electrochemical performances for typical noble metal-carbon composite bifunctional catalysts as cathodes in MABs [86,87,89,91,92,96,100,104].…”

“…For example, composite catalysts such as PtCo 2 /C [89] and Pt/CNTs/Ni [104] can deliver high discharge capacities of 3040 and 4050 mAh g −1 for MABs, respectively. Compared to pure Pt catalysts, other noble metals (e.g., Ir or Ru) are also able to increase OER favoring cycling performances.…”

RuO 2 nanoparticles decorated MnOOH/C as effective bifunctional electrocatalysts for lithium-air battery cathodes with long-cycling stability

“…Typically, the loading density has a strong effect on cycle performance of Li-air battery, because the cycling time is calculated based on loading amount as well as current density. Therefore, control the loading amount of catalysts is necessary to compare with other research results (in fact, most of results were achieved in high current density with a catalyst loading of 0.5 mg cm À2 or low current density with a catalyst loading of 1.0 mg cm À2 ) [23,34,35]. In this study, the Liair cell with 0.5 mg cm À2 of catalyst loading was cycled at a current density of 0.2 mA cm À2 with a limited capacity of 1000 mAh g À1 .…”

Recent Progress on Stability Enhancement for Cathode in Rechargeable Non‐Aqueous Lithium‐Oxygen Battery

“…Various types of materials including metals, [122][123][124] metal oxides, [125][126][127][128] and transition bimetallic nitrides, [ 129,130 ] have been investigated. The charge voltage of the Li-O 2 battery with these catalysts is lowered to some extent, which can benefi t the chemical stability enhancement of carbon cathode.…”