Electrospun Sb/C Fibers for a Stable and Fast Sodium-Ion Battery Anode

TLDR

Sodium‑ion batteries are attractive for large‑scale renewable storage because of their low cost and abundant sodium, yet anode research has largely focused on carbon materials with limited exploration of high‑capacity alloy options. This work aims to create a high‑capacity, stable anode by fabricating antimony nanoparticles uniformly embedded in one‑dimensional carbon fibers. The antimony/carbon composite (SbNP@C) was produced via a scalable electrospinning process that yields ~30 nm Sb nanoparticles encapsulated within 400 nm carbon fibers. The binder‑free, current‑collector‑free SbNP@C electrode delivers an initial capacity of 422 mAh g⁻¹, retains 350 mAh g⁻¹ after 300 cycles at 100 mA g⁻¹, and maintains high capacities at elevated currents thanks to efficient 1D ion transport and a conductive network, enabling high‑power operation.

Abstract

Sodium-ion batteries (SIBs) are considered a top alternative to lithium-ion batteries (LIBs) for large-scale renewable energy storage units due to their low cost and the abundance of sodium-bearing precursors in the earth's mineral deposits. However, the development of anode materials for SIBs to date has been mainly limited to carbonaceous materials with minimal research devoted to high capacity alloy-based materials. In this study, an antimony (Sb)/carbon (C) electrode with ~30 nm Sb nanoparticles (NPs) uniformly encapsulated in interconnecting one-dimensional (1D) 400 nm carbon fibers (denoted as SbNP@C) was fabricated using a simple and scalable electrospinning method. This binder-free, current collector-free SbNP@C electrode demonstrated high capacity and stable long-term cycling performance at various current densities. The SbNP@C electrode showed an initial total capacity of 422 mAh/gelectrode and retained 350 mAh/gelectrode after 300 deep charge-discharge cycles under 100 mA/gSb. Moreover, because of the efficient 1D sodium-ion transport pathway and the highly conductive network of SbNP@C, the electrode preserved high overall capacities even when cycled at high currents, extending its usability to high power applications.