Carbon-Confined Two-Dimensional Sodiophilic Sites Boosted Dendrite-Free Sodium Metal Anodes

Abstract

Carbon-supported sodium metal anodes (SMAs) have attracted growing interest in next-generation energy storage applications. Sodiophilic sites on carbon hosts such as foreign metal/metal compounds are critical for suppressing Na dendrite growth. However, the foreign active materials are mostly restricted to nanoparticle-like structures, which suffer from severe agglomeration and low metal utilization. Here, we develop the carbon-encapsulated mosaic Fe3O4 nanosheets (Fe3O4@CNS) with two-dimensional (2D) active sites via the oriented attachment (OA) mechanism. Ultrathin Fe3O4 nanosheets not only endow the carbon hosts with a continuous 2D nucleation region and high metal utilization but also catalyze the formation of a stable solid electrolyte interphase (SEI) film. Additionally, carbon shells can protect the Fe3O4 against electrolyte exfoliation. As a result, the Fe3O4@CNS half cells achieve a cycle of up to 1800 h with an average Coulombic efficiency (CE) of 99.6% at 1.0 mA cm–2 and 1.0 mA h cm–2 and still stably cycle for 800 h with a high CE of 99.2% even at 3.0 mA cm–2 and 3.0 mA h cm–2. The Na@Fe3O4@CNS symmetric cells can last for more than 2200 h at 1.0 mA cm–2 and 1.0 mA h cm–2. And the Na3V2(PO4)3 || Na@Fe3O4@CNS full cells can attain a specific capacity of 86.6 mA h g–1 after 350 cycles at 1.0 A g–1 (∼8C), showing excellent cycle stability for practical applications. This work provides a new method to establish efficient 2D nucleation sites in the Na hosts.

Na metal anodes for liquid and solid-state Na batteries

“…This breakthrough allows for enhanced ionic transfer kinetics within the electrode, leading to improved energy density and longerlasting performance. 430,431 This advancement aims to facilitate the practical use of high current and areal capacity in the NMBs. Additionally, research and development in the field of the NMBs, require a deep understanding of materials science, electrochemistry, and engineering.…”

Wide-temperature-range sodium-metal batteries: from fundamentals and obstacles to optimization

“…177,189 Na dendrites as a trigger for SMB security have not been completely inhibited, and their potential generation principles have not been clearly exposed. 190 Many efforts have been placed into probing the mechanism of formation of Na dendrites and their evolutionary process. 155,191 A sequential growth mechanism has been proposed to explain the growth of Na dendrites.…”

Promoting the Cation Utilization in Energy‐Dense Sodium Metal Battery Prototypes: Strategies, Analysis, and Prospects

“…[41] In conclusion, the selection of appropriate electrolytes, especially those based on ether solvents, plays a critical role in achieving stable and dendrite-free sodium metal anodes in advanced battery systems. [5,6,[14][15][16]32,34,[75][76][77][78][79][80][81][82][83][84][85][86][87] Figure 5. Electrolyte modification strategies: a) LUMO and HOMO levels of ether solvents (DME, DEGDME, and TEGDME) and carbonate solvents (EC, DEC, and PC); [37,88] Copyright 2018, Wiley-VCH.…”

“…Figure 4. Dendrite-free Na metal anode modification strategy [5,6,[14][15][16]32,34,[75][76][77][78][79][80][81][82][83][84][85][86][87]. …”