A 3D Hydroxylated MXene/Carbon Nanotubes Composite as a Scaffold for Dendrite‐Free Sodium‐Metal Electrodes

Benefiting from abundant resource reserves and considerable theoretical capacity, sodium (Na) metal is a strong anode candidate for low‐cost, large‐scale energy storage applications. However, extensive volume change and mossy/dendritic growth during Na electrodeposition have impeded the practical application of Na metal batteries. Herein, a self‐sodiophilic carbon host, lignin‐derived carbon nanofiber (LCNF), is reported to accommodate Na metal through an infiltration method. Na metal is completely encapsulated in the 3D space of the LCNF host, where the strong interaction between LCNF and Na metal is mediated by the self‐sodiophilic sites. The resulting LCNF@Na electrode delivers good cycling stability with a low voltage hysteresis and a dendrite‐free morphology in commercial carbonate‐based electrolytes. When interfaced with O3‐NaNi0.33Mn0.33Fe0.33O2 and P2‐Na0.7Ni0.33Mn0.55Fe0.1Ti0.02O2 cathodes in full cell Na metal batteries, the LCNF@Na electrode enables high capacity retentions, long cycle life, and good rate capability. Even in a “lean” Na anode environment, the full cells can still deliver good electrochemical performance. The overall stable battery performance, based on a self‐sodiophilic, biomass‐derived carbon host, illuminates a promising path towards enabling low‐cost Na metal batteries.

“…In contrast, these carbon hosts without self‐sodiophility exhibit severe dendrites growth and inferior cycling stability. [ 32–37 ]…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Self‐Sodiophilic Carbon Host Promotes the Cyclability of Sodium Anode

Tao

et al. 2020

“…Recently, Chen and co‐workers synthesized a flexible and stable 3D hydroxylated MXene/carbon nanotubes (h‐Ti 3 C 2 /CNTs) composite as a host for Na‐metal anode (Figure 15k). [ 219 ] The hydroxylated fibrous MXene (h‐Ti 3 C 2 ) has abundant sodiophilic oxygenic and fluoric functional groups, which could not only effectively lower the nucleation overpotential but also induce uniform Na nucleation and deposition. Due to the superior mechanical property, excellent thermal conductivity, abundant sodiophilic sites, and rapid electron/Na + transport kinetics of the host, the h‐Ti 3 C 2 /CNTs/Na composite anode exhibited an excellent electrochemical performance.…”

Section: The Application Of Mxene In Metal Anodesmentioning

confidence: 99%

Recent Advances of Emerging 2D MXene for Stable and Dendrite‐Free Metal Anodes

Wei

Yuan

et al. 2020

170

Metal anodes based on a plating/stripping electrochemistry such as metallic Li, Na, K, Zn, Mg, Ca, Al, and Fe have attracted widespread attention over the past several years because of their high theoretical specific capacity, low electrochemical potential, and superior electronic conductivity. Metal anodes can be paired with cathodes to construct high-energy-density rechargeable metal batteries. However, inherent issues including large volume changes, uncontrollable growth of dangerous dendrites, and an unstable solid electrolyte interphase (SEI) hinder their further development. MXene as an emerging 2D material has shown great potential to address the inherent issues of metal anodes due to its 2D structure, abundant surface functional groups, and the ability to construct macroscopic architectures. To date, under the assistance of MXene, various strategies have been proposed to achieve stable and dendrite-free metal anodes, such as MXene-based host design, designing metalphilic MXene-based substrates, modifying the metal surface with MXene, constructing MXene arrays, and decorating separators or electrolytes with MXene. Herein the applications and advances of MXene in stable and dendrite-free metal anodes are carefully summarized and analyzed. Some perspectives and outlooks for future research are also proposed.

“…Massive efforts have been devoted to tackle the daunting challenge of Na dendrite formation, mainly encompassing electrolyte/additive optimization, [ 12–17 ] artificial solid electrolyte interphase (SEI) stabilization, [ 18–21 ] and 3D host fabrication. [ 22–28 ] In particular, constructing 3D Na hosts have readily drawn much attention as an effective solution to inhibit dendrite formation throughout declining local current, promoting sodiophilic chemistry and cushioning volume change. Na foil could easily deform upon electrochemical cycling owing to its low metallic bonding energy, thereby aggravating the dendrite growth.…”

Section: Introductionmentioning

confidence: 99%

Synchronous Promotion in Sodiophilicity and Conductivity of Flexible Host via Vertical Graphene Cultivator for Longevous Sodium Metal Batteries

Gao

Liu

et al. 2021

Sodium (Na) metal batteries are nowadays appealing due to high specific capacity and low cost. However, major caveats including severe Na dendrite growth, unstable solid electrolyte interphase formation, and poor mechanical robustness have hampered its practicability. In this report, a highly sodiophilic and conductive host harnessing hierarchical vertical graphene (VG) cultivator and Co nanoparticle/N‐doped carbon decorator (Co‐VG/CC) is designed to accommodate Na metal throughout a facile infusion route. The strong interaction between Co‐VG/CC and Na is realized by sodiophilic Co nanoparticle/N‐doped carbon hybrid, resulting in excellent structural stability of the electrode. The well‐regulated Na adsorption behavior and uniform stripping/plating mechanism is systematically investigated via theoretical simulation in harmonization with in situ/ex situ electroanalytical analysis. In consequence, as‐derived Na@Co‐VG/CC electrode effectively inhibits the dendrite formation, resulting in promising electrochemical performances in symmetric cell configuration (functioning at an elevated rate of 5.0 mA cm−2 under 5.0 mAh cm−2 for 280 h, delivering a high capacity of 6.0 mAh cm−2 at 3.0 mA cm−2 for 1000 h and maintaining an ultralong lifespan up to 2000 h). Meanwhile, assembled flexible Na metal battery full cell can sustain to work for 120 h, representing a great advance in practical energy storage applications.