Directed-regulation sodium metal deposition behavior and electrode interfacial structure via surface anchoring effect enable long-life and dendrite-free sodium metal anode

Abstract

Sodium metal batteries (SMBs) fail to meet practical application metrics due to uncontrollable dendrite growth, undesired electrode interfacial side reactions, and infinite volume change during the stripping/plating process. Herein, a triple functional sodiophilic Ti₃C₂T_x-MXene-modified 3D conductive carbon cloth (Ti₃C₂T_x-MXene@CC) is elaborately designed to directed-regulation Na metal deposition behavior and electrode interfacial structure, as well as alleviate the volume change during cycling. Initially, the sodiophilic Ti₃C₂T_x-MXene nanosheets exploit their surface anchoring effect to induce Na metal along the surface of nanosheet deposition, thereby suppressing the dendrites growth. Simultaneously, introducing sodiophilic seeds facilitates the formation of stable NaF-rich solid electrolyte interface film on the electrode surface, improving Na deposition dynamics and uniformity. Then, the high specific surface area and open 3D structure of the CC skeleton effectively reduce the local current density and accommodate the Na deposits. Consequently, the Ti₃C₂T_x-MXene@CC electrode enables symmetric cells to cycle over 2000 h with a stable overpotential of 21 mV at 4 mA cm⁻²/1 mA h cm⁻². And the assembled Na-Ti₃C₂T_X-MXene@CC||NVPOF full cells deliver a high capacity of 114.8 mA h g⁻¹ over 1300 cycles with an excellent capacity retention of 96.4 %, demonstrating the superiority of Ti₃C₂T_X-MXene@CC electrode in the construction of high-performance SMBs.