Interfacial Phonon Scattering Enables Ultrastable and High‐Power Sodium‐Based Dual‐Ion Batteries With Alloying Anodes

Alloying anodes offer a compelling route to high-energy sodium-based dual-ion batteries (SDIBs), yet their repeated volume change accumulates destructive strain energy that rapidly degrades the electrode. Conventional interfacial designs often dissipate this energy through damage-prone processes (e.g., cracking or delamination), which accelerates failure. Herein, we report a crystal-plane friction interface (CPFI) strategy that enables a fundamentally different, low-damage dissipation pathway. By embedding layered Na+-substituted α-zirconium phosphate (NZrP) nanoparticles into a polymer matrix, we construct a robust interface on Sn anode as a proof of concept. The accumulated strain energy is relieved through facile sliding between the NZrP (002) planes, which convert mechanical work into thermal phonons. In situ stress measurements confirm a 99.1% reduction in strain energy density, directly quantifying the efficacy of this mechanism. Meanwhile, Na+ substitution in NZrP facilitates rapid Na+ transport, achieving a substantial ∼65% reduction in interfacial impedance. Consequently, the Sn@CPFI anode enables SDIB full cells that retain over 80% capacity over 3500 cycles at 5C and deliver 90.1% capacity retention at 40C, significantly outperforming conventional counterparts. A practical pouch cell further validates this approach. This work establishes crystal-plane sliding as a general mechanism for managing strain energy, opening a pathway to durable batteries with high-volume-change electrodes.