Nanoemulsion-Coated Ni–Fe Hydroxide Self-Supported Electrode as an Air-Breathing Cathode for High-Performance Zinc–Air Batteries

Abstract

To improve the energy conversion efficiency and durability of zinc–air batteries (ZABs) for large-scale implementations, here we propose an “air-breathing” strategy to significantly enlarge triple-interfaces with intensified mass transfer. By dip-coating the aerophilic perfluorochemical compounds (PFC) and amphiphilic ionomers into the self-supported electrodes, (1) the high solubility of O2 in the PFC nanoemulsions greatly increases triple-phase boundaries and facilitates the efficient supply/removal of O2 from the electrolyte; (2) the ionomers with hydrophobic and hydrophilic functionalities enable fast gas, water, and ion transport to the triple-phase boundaries; and (3) the self-supported electrode without binder ensures fast electron transfer while the firm integration prevents catalyst shedding. By applying this strategy, the ZABs show a high power density of 115 mW cm–2 and a narrow discharge/charge gap of 0.64 V at 10 mA cm–2 and a long-cycling durability (over 1000 h). This work provides a universal approach to promote gas-evolving reactions for electrochemical applications.

Engineering Self‐Supported Hydrophobic–Aerophilic Air Cathode with CoS/Fe3S4 Nanoparticles Embedded in S, N Co‐Doped Carbon Plate Arrays for Long‐Life Rechargeable Zn–Air Batteries

“…[24,25] To maximize mass transfer efficiency and achieve complete exposure to active catalytic sites, some strategies have been developed to modulate the hydrophobicity of air electrodes. [26,27] For instance, polytetrafluoroethylene (PTFE) waterproofing has conventionally been used to increase the hydrophobic properties of air electrodes in metal-air batteries. [24,28,29] Unfortunately, these strategies to utilize hydrophobic polymers or waxy alkanethiols coated on the catalyst surface will sacrifice its activity due to the remarkable reduction of the specific surface area of the electrodes, and the excess use of such hydrophobic materials may even block active catalytic sites or render the electrode completely hydrophobic.…”

Key components and design strategy of the membrane electrode assembly for alkaline water electrolysis

“…NiFe-based layered double hydroxides (LDHs), known to be excellent OER catalysts with high intrinsic activity, have been widely employed for alkaline water electrolysis. [106][107][108][109] Much research has been devoted to increasing the electrochemical surface area and active sites of NiFe LDHs through size control 110,111 and morphology design. [112][113][114] Hiroyuki et al used a liquid phase reaction to synthesize NiFe LDHs with a lateral size Energy & Environmental Science Review of o10 nm (Fig.…”

Recent Advances of Electrocatalyst and Cell Design for Hydrogen Peroxide Production

“…This can effectively circumvent the problem of the low solubility of oxygen. The integrated electrodes with the advantages of fast electron transfer were constructed to reinforce the gas-diffusion channels against destruction by coating them with a thin gas-diffusion layer [ 163 , 164 ]. Moreover, the established gas-diffusion layers can mitigate the H 2 O 2 corrosion process towards the catalyst and the substrate, thus enhancing the stability and durability of catalysts.…”