An MXene-Based Metal Anode with Stepped Sodiophilic Gradient Structure Enables a Large Current Density for Rechargeable Na-O<sub>2</sub> Batteries.
basic_science · Level V
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- Record sourced from PubMed, PMID 35130361.
- Also identified by DOI 10.1002/adma.202106565.
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Abstract
The metal anode is the pivotal component for advanced sodium-metal batteries such as Na-O<sub>2</sub> batteries. Designing a 3D confinement scaffold is a promising strategy for constructing dendrite-free sodium-metal anodes; however, cycling stability at a large current density (>10 mA cm<sup>-2</sup> ) is still difficult to realize. Herein, the design of new lightweight and fibrous hydroxylated Ti<sub>3</sub> C<sub>2</sub> (h-Ti<sub>3</sub> C<sub>2</sub> ) MXene based scaffolds with stepped sodiophilic gradient structure (h-M-SSG) is reported, and its thickness can be controlled (80-250 µm). The sodiophilic gradient structure (adjusted by h-Ti<sub>3</sub> C<sub>2</sub> ) can effectively induce sodium ions to preferentially deposit at the bottom of the scaffold, thus inhibiting dendrite growth. h-M-SSG/Na-based symmetrical batteries exhibit a low polarization voltage and long cycling life at a high current density (40 mA cm<sup>-2</sup> ) and a high cut-off capacity (40 mAh cm<sup>-2</sup> ). Moreover, a Na-O<sub>2</sub> battery with an h-M-SSG/Na anode exhibits a low potential gap of 0.137 V after 45 cycles at 1000 mA g<sup>-1</sup> and 1000 mAh g<sup>-1</sup> . This deposition-regulation strategy would inspire the design of 3D scaffolds for high-performance sodium-metal-anode-based batteries.