Hierarchical Co₃O₄ Nanofiber–Carbon Sheet Skeleton with Superior Na/Li‐Philic Property Enabling Highly Stable Alkali Metal Batteries

Abstract

(1 of 10)Uncontrollable dendritic behavior and infinite volume expansion in alkali metal anode results in the severe safety hazards and short lifespan for high-energy batteries. Constructing a stable host with superior Na/Li-philic properties is a prerequisite for commercialization. Here, it is demonstrated that the small Gibbs free energy change in the reaction between metal oxide (Co 3 O 4 , SnO 2 , and CuO) and alkali metal is key for metal infusion. The as-prepared hierarchical Co 3 O 4 nanofiber-carbon sheet (CS) skeleton shows improved wettability toward molten Li/Na. The 3D carbon sheet serves as a primary framework, offering adequate lithium nucleation sites and sufficient electrolyte/electrode contact for fast charge transfer. The secondary framework of Co/Li 2 O nanofibers provides physical confinement of deposited Li and further redistributes the Li + flux on each carbon fiber, which is verified by COMSOL Multiphysics simulations. Due to the uniform deposition behavior and near-zero volume change, modified symmetrical Li/Li cells can operate under an ultrahigh current density of 20 mA cm −2 for more than 120 cycles. When paired with LiFePO 4 cathodes, the Li/Co-CS cell shows low polarization and 88.4% capacity retention after 200 cycles under 2 C. Convincing improvement can also be observed in Na/Co-CS symmetrical cells applying NaClO 4 -based electrolyte. These results illustrate a significant improvement in developing safe and stable alkali metal batteries.

Regulating Lithium Nucleation and Deposition via MOF‐Derived Co@C‐Modified Carbon Cloth for Stable Li Metal Anode

“…Besides, CC@CN‐Co@Li//Li symmetry cell was cycled at 2 mA cm −2 for 1 mA h cm −2 after 100 cycles to confirm its enduring stability ( Figure and Figure S8, Supporting Information). The homogenous electrodeposition guides Li conformably adhere on the lithiophilic CC@CN‐Co framework without unwanted separation, which is free of bulging or smashing after cycling, evidencing framework has excellent structural solidity in resisting repeated stripping/plating process 35…”

“…In contrast, Li foil symmetric coin cell exhibits constant voltage rise and fluctuation in each charge and discharge process during the initial cycles, which demonstrates mossy‐like dendrite growth 5,33. As the cycle progresses, Li foil exhibits a gradual voltage polarization augment at 50 h, which may be owing to the accumulation of charge transfer resistance and the dendrite growth 34,35. High initial overpotential value and fluctuant voltage profile are obviously observed in the CC@Li electrode, with unstable voltage hysteresis profiles.…”

A Sodiophilic Interphase‐Mediated, Dendrite‐Free Anode with Ultrahigh Specific Capacity for Sodium‐Metal Batteries

“…Generally, these strategies mainly concentrate on the already formed Na plating morphology, that is, Na dendrites, yet few involve the initial Na deposition behavior, including the nucleation. However, the final Na morphology significantly depends on the initial nucleating behavior, especially upon the realistic application requiring high areal capacity (for example, 10 mAh cm −2 ) . Several efforts have been made to improve the Na/Li nucleation process by the introduction of heteroatom (for example, N and S) into current collectors while the yielding anodes demonstrated limited capacities .…”

“…However,t he final Na morphology significantly depends on the initial nucleating behavior, especially upon the realistic application requiring high areal capacity (for example,10mAh cm À2 ). [5,[16][17][18] Several efforts have been made to improve the Na/Li nucleation process by the introduction of heteroatom (for example,N and S) into current collectors while the yielding anodes demonstrated limited capacities. [5,14] As ar esult, the Na anodes generally exhibit very poor stability when cycled at high areal capacity.Although there are some reports on long cycling life of > 1000 hi nN aa nodes,t hese high stabilities have only been achieved at very low Na areal capacity ( 2mAh cm À2 ).…”

A Sodiophilic Interphase‐Mediated, Dendrite‐Free Anode with Ultrahigh Specific Capacity for Sodium‐Metal Batteries

“…[14,15] Generally,t hese strategies mainly concentrate on the already formed Na plating morphology,t hat is, Na dendrites,y et few involve the initial Na deposition behavior, including the nucleation. [5,[16][17][18] Several efforts have been made to improve the Na/Li nucleation process by the introduction of heteroatom (for example,N and S) into current collectors while the yielding anodes demonstrated limited capacities. [5,[16][17][18] Several efforts have been made to improve the Na/Li nucleation process by the introduction of heteroatom (for example,N and S) into current collectors while the yielding anodes demonstrated limited capacities.…”