Anthraquinone Covalent Organic Framework Hollow Tubes as Binder Microadditives in Li−S Batteries

Abstract

The exploration of new application forms of covalent organic frameworks (COFs) in LiÀSb atteries that can overcome drawbacks like lowconductivity or high loading when typically applied as sulfur host materials (mostly % 20 to % 40 wt %l oading in cathode) is desirable to maximizet heir low-density advantage to obtain lightweight, portable,orhighenergy-density devices.H ere,w ee stablish that COFs could have implications as microadditives of binders ( % 1wt% in cathode), and as eries of anthraquinone-COF based hollow tubes have been prepared as model microadditives.T he microadditives can strengthen the basic properties of the binder and spontaneously immobilize and catalytically convert lithium polysulfides,a sp roved by density functional calculations,thus showing almost doubly enhanced reversible capacity compared with that of the bare electrode.

Metal–Organic Framework-Derived Fe-Doped Ni3Se4/NiSe2 Heterostructure-Embedded Mesoporous Tubes for Boosting Oxygen Evolution Reaction

“…Moreover, SEM analysis was employed in elucidating the morphology of MOFs and their derivatives. As shown in Figure a, the SEM image of Ni-MOF confirms the unique nanosheet self-assembled hollow tube morphology (Figure S3), which is found to be very rare. , Notably, carbonization of Ni-MOFs in a sublimated Fe-atmosphere resulted in the formation of a mesh-like tubular network due to the decomposition of the MOF nanostructure (Figure b,c). While the same experiment performed under Se-vapor resulted in the partial decomposition of nanosheets on hollow tubes, the nanosheets have vanished in most places, resulting in crowbar-type hollow tubes (Figure d–f).…”

“…As shown in Figure 2a, the SEM image of Ni-MOF confirms the unique nanosheet self-assembled hollow tube morphology (Figure S3), which is found to be very rare. 52,53 Notably, carbonization of Ni-MOFs in a sublimated Fe-atmosphere resulted in the formation of a mesh-like tubular network due to the decomposition of the MOF nanostructure (Figure 2b,c 3d), while the lattice fringes with a 0.293 nm interplanar distance detected in other areas confirm the (020) crystal plane of NiSe 2 nanoparticles (locations 2 and 3 of Figure 3d). 12,14 Moreover, abundant hetero-interfaces have been detected between Ni 3 Se 4 and NiSe 2 nanoparticles, which can possess electrochemically active lattice distortions, dislocations, and defective sites (Figures 3e and S5c).…”

Donor–Acceptor Conjugated Microporous Polymer toward Enhanced Redox Kinetics in Lithium–Sulfur Batteries

“…Lithium–sulfur (Li–S) batteries are recognized as one of the most promising alternatives for new generation energy storage devices due to their ultrahigh intrinsic capacity (1675 mAh g –1 ) and theoretical specific energy density (2600 Wh kg –1 ) as well as the low price and environmental friendliness of sulfur. − However, the practical use and commercialization of Li–S batteries still face many challenges, such as low sulfur utilization, irreversible capacity fading and low Coulombic efficiency, which are mainly caused by the insulation of solid elemental sulfur and lithium sulfide (Li 2 S), the huge volume fluctuation of the sulfur cathode and the shuttle effect of soluble polysulfide intermediates (LiPSs). − Besides, the electrochemical redox kinetics is always sluggish, especially in the case of lean electrolyte and high sulfur loading, thereby leading to incomplete conversion of active species and apparent LiPS flooding. − …”

Highly Crystalline Polyimide Covalent Organic Framework as Dual-Active-Center Cathode for High-Performance Lithium-Ion Batteries

“…Covalent organic frameworks (COFs) with open channels and tunable structures are an emerging class of crystalline porous polymers and have received tremendous research interest in versatile applications, − including gas storage and separation, − photocatalysis, − heterogeneous catalysis, − sensing, − proton conduction, − and drug delivery − as well as energy storage and conversion. − COFs with target topologies can be designed and constructed in terms of the principle of reticular chemistry . To date, the polygonal skeletons of two-dimensional (2D) COFs are mainly rhombille lattice ( kgd ), hexagonal lattice ( hcb ), triangular lattice ( hxl ), tetragonal lattice ( sql ), and kagome lattice ( kgm ) .…”