Developing high-specific-energy metal batteries (such as lithium/sodium batteries) is of great significance for renewable energy storage. However, metal anodes face core issues including dendrite growth, unstable solid electrolyte interphase (SEI), and structural collapse due to lack of support frameworks, severely limiting practical applications. Current research on stabilizing metal anodes follows two main directions but suffers from shortcomings and lacks systematic design strategies.

Recently, researchers including Professor Dong Quanfeng and Professor Zheng Mingsen from Xiamen University proposed the concept of Reconstructed Metal Anode (RMA), achieving a fundamental transformation of metal anodes. Taking the reconstructed sodium metal anode (RSMA) as an example, the researchers pre-implanted an activatable ion-conductive network and polymer framework to form an RSMA with a 3D self-supporting ion/electron conductive skeleton. They elucidated its effects on electrolyte, SEI formation, and electrochemical performance.

The team used a simple mechanical synthesis method to prepare the mixed metal salt framework of RSMA, altering the structural stability and interaction mode of sodium metal. Sodium hexafluorophosphate (NaPF₆) is activated by the electrolyte and enriched at the electrode/electrolyte interface in a confined solvated state, constructing a 3D reaction zone that enables uniform Na⁺ entry for high-dimensional deposition/stripping, achieving rapid penetration and electron transport. Retained NaPF₆ and PPy serve as a 3D salt framework supporting the entire electrode. Meanwhile, PF₆⁻ decomposition becomes the main source of SEI components, eliminating the need for cumbersome solvation structure adjustments.

Experimental results showed that symmetric cells with RSMA composite electrodes achieved stable cycling for hours to tens of hours in carbonate electrolytes under various current densities and capacities. Thin RSMA electrodes loaded on copper achieved 100% DOD cycling. RSMA||PB full cells delivered excellent long-term cycling, rate performance, variable-temperature operation, and long cycling at high current densities. A proof-of-concept pouch cell achieved high energy density and good capacity retention, setting a new record for pouch cells. Additionally, superior performance compared to other sodium salts and lithium-ion batteries demonstrates the broad application prospects of the RMA concept and strategy.

The paper points out that the greatest challenge for metal anodes is the reaction interface being limited to two-dimensional space, necessitating fundamental reshaping. The RMA concept and strategy produce a sodium metal anode that is an activatable self-supporting 3D ion/electron conductive "metal-polymer-salt" framework, expanding the reaction zone to three dimensions. A series of battery configurations confirmed the feasibility of metal reconstruction, with battery performance surpassing most reported literature. This design differs from previous studies, not only providing new ideas for overcoming poor SMB stability but also fundamentally addressing structural instability of metal anodes. From a practical perspective, the roll-pressing preparation method is convenient, safe, and economical. The design and performance of metal anodes represented by RSMA offer valuable concepts and strategies for studying the reversibility of anode deposition/stripping, and the concept and strategy can be extended to other salt and alkali metal electrode systems, providing a theoretical foundation and implementation path for designing efficient, long-life energy storage systems.