Electrospun Interconnected Bead-Like P2-NaxCoyMn1-yO2 (x=0.66, y=0.1) Cathode Material for Stable Sodium-Ion Storage

Abstract

The development of high-rate and long-cycle-life Na-based cathode materials, on par with the performance of commercialized lithium-based cathodes, is crucial to satisfy the recurring surge in energy demand. Here, we report an interconnected bead-like P2-type manganese-based oxide NaxCoyMn1-yO2 (x = 0.66, y = 0.1) synthesized by electrospinning and subsequent heat treatment as a high-rate cathode material for sodium-ion batteries (SIBs). The employed strategy of one-dimensional morphological design with interconnected bead-like particles profusely enhances Na+ diffusion pathways. This layered cathode material exhibits a stable and superior discharge capacity of 180.0 mAh g(-1) at 50 mA g(-1) compared to a bare cathode material synthesized via the sol-gel process. Further, a high capacity of 78.3 mAh g(-1) was achieved, maintaining excellent capacity retention of 85.0% even after 500 insertion/desertion cycles implying robust Na+ storage properties. High-rate tests also revealed promising electrochemical performances at C-rates as high as 5000 mA g(-1), affirming the potential of this layered cathode material for high-rate Na+ storage. Additionally, full SIBs assembled with a NaxCoyMn1-yO2 (x = 0.66, y = 0.1) cathode and a carbon nanofiber (CNF) anode exhibited a high cycle performance, retaining 96.3 mAh g(-1) after 100 cycles at 300 mA g(-1).