Development of a Hydrophobic Ni0.5Mn0.5Co2O4 Catalyst for Mitigating Moisture-Induced Degradation in Li-Air Batteries

Abstract

Lithium-air (Li-air) batteries are a promising candidate for next-generation energy storage technology. However, their practical development is limited by cathode channel clogging and moisture induced degradation. In this work, a Ni_0.5Mn_0.5Co₂O₄-loaded 3D sodium alginate gel was synthesized as an efficient catalyst for Li-air batteries. To further enhance its performance, a hydrophobic treatment was applied to the catalyst, which significantly reduced the formation of by-products and the lifespan of the Li-air battery in humid atmospheres was extended. At a current density of 500 mA g⁻¹, the modified Li-air batteries demonstrated remarkable cycle stability, achieving 142 cycles in pure oxygen, 91 cycles in ambient air (∼40% relative humidity, RH), and 58 cycles in humid oxygen (∼55% RH, threefold increase compared to unmodified cells). Additionally, the discharge cut-off capacities were significantly enhanced, reaching 19876.5 mAh g⁻¹ and 16465.6 mAh g⁻¹ at a current density of 200 mA g⁻¹ in ambient air and humid oxygen, respectively.