Transition metal phosphides (CoP, etc.), featuring rich natural abundance and remarkable theoretical capacity, suffer from extremely poor rate capability and severe energy decay for sodium storage due to their huge volume change and low electronic conductivity. Herein, an elaborate hierarchical superstructure, nitrogen-doped carbon wrapped CoP in-situ anchored on Ti₃C₂T MXene (CoP@NC/Ti₃C₂T), was fabricated by crosslinking ZIF-67 on Ti₃C₂T flakes followed by successive carbonization and phosphorization. In principle, the dual modification for CoP nanoparticles through NC coating and Ti₃C₂T support can dramatically accelerate the ionic/electronic transportation and alleviate the structure change upon repeated sodiation/desodiation, thus leading to superior electrode integrity, modified ohmic polarization, and excellent electrochemical reversibility. Consequently, the elaborated hierarchical superstructure delivers impressive sodium storage performances with large capacity (396.06 mA·h/g at 0.1 A/g up to 100 cycles), robust rate performance (237.8 mA·h/g at 2.0 A/g), and satisfied cyclability (capacity retention of 81.3% at 1.0 A/g after 1,200 cycles). In principle, systematic electrochemical and characterizations measurements manifest that the high pseudocapacitive effect to charge storage, enhanced ionic diffusion kinetics, and remarkable electrochemical reversibility contribute to the impressive sodium storage performance of target CoP@NC/Ti₃C₂T. Importantly, the unique modification strategy reported in this study paves a way to fabricate high-performance electrode for SIBs.

Sodium metal is one of the ideal anodes for high-performance rechargeable batteries because of its high specific capacity (~ 1166 mAh·g⁻¹), low reduction potential (−2.71 V compared to standard hydrogen electrodes), and low cost. However, the unstable solid electrolyte interphase, uncontrolled dendrite growth, and inevitable volume expansion hinder the practical application of sodium metal anodes. At present, many strategies have been developed to achieve stable sodium metal anodes. Here, we systematically summarize the latest strategies adopted in interface engineering, current collector design, and the emerging methods to improve the reaction kinetics of sodium deposition processes. First, the strategies of constructing protective layers are reviewed, including inorganic, organic, and mixed protective layers through electrolyte additives or pretreatments. Then, the classification of metal-based, carbon-based, and composite porous frames is discussed, including their function in reducing local deposition current density and the effect of introducing sodiophilic sites. Third, the recent progress of alloys, nanoparticles, and single atoms in improving Na deposition kinetics is systematically reviewed. Finally, the future research direction and the prospect of high-performance sodium metal batteries are proposed.