Recent Advances in Stabilization of Sodium Metal Anode in Contact with Organic Liquid and Solid‐State Electrolytes

Abstract

Sodium (Na) metal is considered as the promising anode for next‐generation high‐energy‐density Na‐metal batteries owing to its highest specific capacity and lowest electrochemical potential among all Na‐based anode candidates. However, the Na metal anode suffers from considerable volume change, nonuniform Na deposition, and an unstable electrode–electrolyte interface, which result in rapid capacity fade and poor cycling stability, hampering its practical application. To tackle aforementioned issues, many strategies have been developed to accommodate and guide Na nucleation/growth as well as stabilize the interface, including structure stabilization by applying 3D host materials, electrolyte modification and interface engineering to form stable interfaces and guide the Na deposition, etc. The present review is intended as a guideline through the fundamental challenges affecting the performance of Na metal anodes along with corresponding mitigation strategies. Moreover, the specific mechanisms for stabilizing Na metal anodes are discussed in detail. Apart from the stabilization of the Na metal anode in contact with liquid electrolytes, attention has also been paid to the review of stabilization of the Na metal anode in contact with solid‐state electrolytes. Furthermore, unresolved challenges and promising perspectives for stable Na metal anodes in practical applications are presented.

Freestanding MXene‐based macroforms for electrochemical energy storage applications

“…This behavior leads to the metal dendrite formation after repeated charge/discharge cycles, resulting in a short circuit or safety issues for the battery device. In addition, due to their host‐free nature, metal anodes suffer large volume changes during the plating/stripping process, which worsens the interfacial ionic transport 146 …”

“…In addition, due to their host-free nature, metal anodes suffer large volume changes during the plating/stripping process, which worsens the interfacial ionic transport. 146 To suppress the above-mentioned issues associated with the metal anodes, a variety of strategies have been developed. For instance, the strategy of employing 3D hosts with metal-philic functional groups to homogenize the electric field and ion flux hereby guide uniform nucleation and deposition of metal ions was developed.…”

Pressureless all‐solid‐state Na/S batteries with self‐supporting Na5YSi4O12 scaffolds

“…Therefore, the development of room‐temperature (RT) Na + ionic conductors and safer sodium batteries such as SSBs is of great significance 33–35 . Nonetheless, SSBs operating at RT usually suffer from a very high interfacial impedance due to the poor solid–solid contact at the interfaces between the SSE and both electrodes 36–38 . Furthermore, maintaining a stable interface and good contact is also challenging due to the considerable volume changes of active materials, resulting from repeated electrochemical reactions in the electrodes 39,40 .…”

“…Furthermore, maintaining a stable interface and good contact is also challenging due to the considerable volume changes of active materials, resulting from repeated electrochemical reactions in the electrodes 39,40 . The deterioration of interfaces can consequently induce dendrite formation in the anode compartment and underutilize active materials in the cathode, hence causing battery degradation or even failure 37,41,42 . In practice, various strategies are applied to avoid the battery fading of SSBs.…”

“…39,40 The deterioration of interfaces can consequently induce dendrite formation in the anode compartment and underutilize active materials in the cathode, hence causing battery degradation or even failure. 37,41,42 In practice, various strategies are applied to avoid the battery fading of SSBs. For example, the application of external stacking pressure, cosintering of composite electrodes, and modification of interfaces are required to ensure stable interfaces.…”