π‐Conjugation Induced Anchoring of Ferrocene on Graphdiyne Enable Shuttle‐Free Redox Mediation in Lithium‐Oxygen Batteries

Abstract

Soluble redox mediators (RMs), an alternative to conventional solid catalysts, have been considered an effective countermeasure to ameliorate sluggish kinetics in the cathode of a lithium–oxygen battery recently. Nevertheless, the high mobility of RMs leads to serious redox shuttling, which induces an undesired lithium‐metal degeneration and RM decomposition during trade‐off catalysis against the sustainable operation of batteries. Here, a novel carbon family of graphdiyne matrix is first proposed to decouple the charge‐carrying redox property of ferrocene and the shuttle effects. It is demonstrated that a ferrocene‐anchored graphdiyne framework can function as stationary RM, not only preserving the redox‐mediating capability of ferrocene, but also promoting the local orientated three‐dimensional (3D) growth of Li2O2. As a result, the RM‐assisted catalysis in lithium–oxygen battery remains of remarkable efficiency and stability without the depletion of oxidized RMs or lithium degradation, resulting in a significantly enhanced electrochemical performance.

Functional Graphdiyne for Emerging Applications: Recent Advances and Future Challenges

“…[233] The discharging and charging potentials of the N1-GDY-based batteries show a negligible change after 150 h, apparently better than that of the Pt/C-based battery (Figure 10o), confirming the remarkably enhanced stability of N1-GDY. Other kinds of functional GDY-based batteries, such as Fc-modified GDY for Li-O 2 batteries, [55] Cu-doped MoS 2 NB@HsGDY heterostructures for rechargeable magnesium batteries, [87] and Mn 3 O 4 NP@GDY heterostructures for Zn ion batteries, [234] have also been largely exploited for significantly enhanced electrochemical performance.…”

“…The heteroatoms are often incorporated into GDY by (i) rationally designing functional monomers (e.g., 1,3,5‐triethynyl‐2,4,6‐trifluorobenzene, [ 51 ] 2,4,6‐triethynyl‐1,3,5‐triazine [ 52 ] ) as corresponding precursors, (ii) the oxidation of GDY (GDYO) by means of modified Hummer's approach, [ 35 ] and (iii) direct doping by a hydrothermal method (e.g., S‐GDY, [ 53 ] ) or corrosion engineering (e.g., Cl‐doped GDY [ 54 ] ). The molecule (small molecules or macromolecules)‐modified GDY are usually fabricated by solution blending via robust π‐π interaction (e.g., ferrocene (Fc)‐modified GDY, [ 55 ] and hemin/GDY [ 56 ] ), and van der Waals interaction (e.g., poly(vinylidene fluoride) (PVDF)/GDY, [ 57 ] and polyvinylpyrrolidone (PVP)/GDY [ 58 ] ). The interface engineering of GDY modified by other nanostructures (0D, 1D, or 2D morphology) is also frequently employed for the construction of GDY‐based heterostructures by versatile strategies, such as in situ cross‐coupling reaction using HEB as a monomer (e.g., metal (Cr, Mn, Mo, W, and Re) SA/GDY, [ 59 ] and 1D Cu 0.95 V 2 O 5 nanorod (NR)@GDY [ 60 ] ), and self‐assembly (e.g., Co 3 O 4 QD/GDY, [ 61 ] and MXene Ti 3 C 2 T x NS/GDYO [ 62 ] ).…”

Fascinating Bifunctional Electrocatalytic Activity via a Mesoporous Structured FeMnO3@ZrO2 Matrix as an Efficient Cathode for Li–O2 Batteries

“…In addition, uneven nucleation of insoluble and sequestered discharged products (e.g., Li 2 O 2 ) can block the O 2 and electrolyte transmission routes, leading to poor rate capabilities and battery longevities. To solve such issues, air electrodes have been designed with appropriate architectures and effective catalysts, suggesting a promising route toward practical LOBs. − …”

“…To address the poor cycle stability and energy efficiency, several metals (e.g., Pt, Au, Ru) have been employed recently as O 2 electrode catalysts. − Nevertheless, the commercialization of LOBs remains hampered by the high cost of precious metal-based catalysts. Research into low-cost transition-metal oxides, nitrides, carbides, and sulfides, as substitutes for precious metals, should be beneficial for lowering catalyst costs .…”

A Flexible Supercapacitor with High Energy Density Driven by MXene/Deep Eutectic Solvent Gel Polyelectrolyte

“…XPS spectra further reveal the interaction mechanism of relevant components within the DES gel polyelectrolyte. For Li metal in DES gel polyelectrolyte PAM/LiP/MXene (Figure g), five distinct peaks occur at approximately 56.8, 55.4, 55.0, 54.3, and 53.7 eV, ascribed to LiF, Li 2 SO 4 , Li 2 CO 3 , LiCOOR (R for alkyl groups), and Li 2 O, respectively . The binding energy of LiF in LPAM/LiP/MXene exhibits a shift with the addition of LN, owing to the presence of strong electronic interactions between LN and DES.…”