3D freestanding CuO@Copper foam as an anode for potassium ion batteries

Abstract

The use of nanoelectrode materials is an efficient way to improve electrochemical performance of potassium ion batteries (KIBs), due to the large ionic radius and poor reaction kinetics of potassium ions. However, nanoelectrode materials with high specific surface areas and tendency to agglomerate generate unstable solid electrolyte interphase (SEI) films or severe side reactions, resulting in poor performance. Herein, a three-dimensional (3D), freestanding and binder-free electrode of CuO@copper foam (CuO@CF) is synthesized by anchoring nanostructured CuO on copper foam as anode for KIBs. CuO@CF electrode delivers a better initial coulombic efficiency, cycling stability and rate performance than that of nanostructured CuO electrode. Meanwhile, the K+ storage mechanism of CuO anode is further elucidated by in-situ X-ray diffraction (XRD), ex-situ XRD, X-ray photoelectron spectroscopy (XPS), and High-resolution transmission electron Microscope (HR-TEM). The as-prepared 3D freestanding CuO@CF electrode mitigates the degradation of nanostructured CuO electrode and provides a promising anode material for KIBs.