CoO nanoparticle modified N, P co-doped carbon paper as sodium carrier to construct stable anodes for Na-metal batteries.

Sodium (Na) metal batteries such as Na-ion batteries and Na-CO batteries are considered to be excellent alternatives to lithium batteries in terms of their potential applications because of their high specific capacity and low cost. However, the sodium anode showed low efficiency and poor cycling in Na-metal battery performance due to the formation of sodium dendrites and serious corrosion. In this work, nitrogen (N), phosphorus (P) co-doped carbon paper (NP-CP) modified with cobalt tetroxide (CoO) nanoparticles was prepared as the Na anode carrier (CoO@NP-CP), and a sodium-based composite anode (Na-Co@NP-CP) was further prepared by electrodepositing sodium. The experimental results indicate that the N, P and CoO multi-doped carbon paper has good sodiophilicity, which can induce the uniform plating/stripping of Na ions and inhibit the growth of Na dendrites. The N, P doped carbon paper provides a high surface area and tremendous three-dimensional (3D) framework to effectively reduce the areal current density, facilitate the transfer of electrons, and enhance battery life. Therefore, Na-Co@NP-CP based symmetric cells exhibit stable cycling of over 1100 hours at current densities of 1 mA cm and fixed capacity of 1 mA h cm. When the Na-Co@NP-CP anode couples with CO, the assembled batteries can deliver a stable cycling of 165 cycles at current densities of 500 mA g and limited capacity of 500 mA h g. When Na-Co@NP-CP anode couples with NaV(PO) (NVP) cathode, the assembled cells exhibit lower hysteresis and batter cycling performance.