Staging Na/K-ion de-/intercalation of graphite retrieved from spent Li-ion batteries: in operando X-ray diffraction studies and an advanced anode material for Na/K-ion batteries

Abstract

The graphite material from exhausted Li-ion batteries (LIBs) is reused as a favorable anode for Na-ion batteries (NIBs) and K-ion batteries (KIBs) through a recycling treatment. The optimized electrode delivers improved electrochemical performance, such as 162 mA h g⁻¹ in NIBs at 0.2 A g⁻¹ and 320 mA h g⁻¹ in KIBs at 0.05 A g⁻¹. In addition, the insights into Na/K-ion de-/intercalation model evolution and corresponding electrochemical analysis are conducted through in operando X-ray diffraction and a series of other characterization methods, discovering a visible transitional stage for NIBs and an irreversible initial cycle phase transformation for KIBs. In a word, we not only provide a new recycling concept for waste graphite anodes but also carry out a series of significant intercalation mechanism studies, which contribute to anode recycling and shed light on the development of graphite material for promising alternative ion batteries.