Multifunctional interlayer provides a robust interfacial tunnel environment for highly reversible zinc-ion batteries

Intercalation chemistry/engineering has attracted much attention in the development of electrochemical energy storage . This study employs a green synthesis method to insert cetyltrimethylammonium bromide (CTAB) into Cu 2-x Se at room temperature , thereby producing a Cu 2-x Se doped material with an expanded interlayer spacing and a nanoplate array structure. Reversible insertion/extraction of Zn 2+ in Cu 2-x Se-CTAB is facilitated through an intercalation reaction mechanism, as evidenced by ex situ X-ray diffraction (XRD) and ex-situ X-ray photoelectron spectroscopy measurements (XPS). Moreover, the CTAB adsorbed on the surface of the zinc anode can regulate the deposition of Zn 2+ and inhibit the formation of dendrites. Benefiting from the above advantages, Cu 2-x Se-CTAB shows a high specific capacity of 661.4 mAh·g −1 at 0.1 A·g −1 as an electrode material for zinc ion batteries , delivered an extraordinary rate capability of 230.2 mAh·g −1 at 3 A·g −1 and excellent cycling stability. Theoretical calculations further demonstrate that the incorporation of CTAB diminishes the electrostatic repulsion between zinc ions and the matrix, facilitating rapid diffusion kinetics of zinc ions , and effectively mitigating the dissolution and volume expansion of the cathode. In addition, a Zn||Cu 2-x Se-CTAB pouch cell has been assembled, delivering a high capacity of 176 mAh·g −1 at 1.0 A·g −1 after 600 cycles and exhibiting a superior long cycling stability. This work highlights the potential of CTAB as a promising solution, providing new opportunities for the development of high-performance rechargeable ZIBs. This study fabricates a Cu 2-x Se intercalation compound showing expanded interlayer space and nanosheet array features by using a green growth approach, in which cetyltrimethyl ammonium bromide (CTAB) is inserted into Cu 2-x Se at an ambient temperature.