MXene-Scaffolded Planner Mesoporous Carbon with Homogeneous Electric Field Enabling Uniform and Robust SEI for Ultra-Stable Sodium Storage

Abstract

For next-generation sodium-ion batteries, nanostructured porous carbons with high surface areas exhibit enhanced rate performance, yet their commercialization is constrained by insufficient cycling stability. Herein, an insight from electrode architecture by using planar 2D MXene@mesoporous carbon (MXene@mesoC) nanosheets are developed to address this challenge. By precisely modulating, the engineered electrode achieves an ultra-smooth surface, which ensures uniform current density and effectively suppresses localized charge accumulation and result a homogeneous electric field. Combined with the mesopore-induced enrichment of PF₆⁻ anions in the Inner Helmholtz layer and a significantly reduced decomposition energy barrier catalyzed by MXene, a uniform, robust, and NaF-rich solid electrolyte interphase (SEI) is formed. The resulting anode demonstrates exceptional electrochemical performance, including ultra-stable cycling (98.4% capacity retention after 10 000 cycles at 5.0 A g⁻¹), high average Coulombic efficiency (99.98%), and remarkable low-temperature operation (down to −40 °C). Furthermore, the feasibility of inkjet printing these materials into customizable microstructures highlights their potential for flexible and high-loading electrodes. This electrode architecture strategy bridges nanoscale interfacial regulation with macroscopic electrode design, offering a general approach for advanced sodium-ion storage in the future.