Hydrogen substituted graphdiyne as carbon-rich flexible electrode for lithium and sodium ion batteries

Abstract

Organic electrodes are potential alternatives to current inorganic electrode materials for lithium ion and sodium ion batteries powering portable and wearable electronics, in terms of their mechanical flexibility, function tunability and low cost. However, the low capacity, poor rate performance and rapid capacity degradation impede their practical application. Here, we concentrate on the molecular design for improved conductivity and capacity, and favorable bulk ion transport. Through an in situ cross-coupling reaction of triethynylbenzene on copper foil, the carbon-rich frame hydrogen substituted graphdiyne film is fabricated. The organic film can act as free-standing flexible electrode for both lithium ion and sodium ion batteries, and large reversible capacities of 1050 mAh g−1 for lithium ion batteries and 650 mAh g−1 for sodium ion batteries are achieved. The electrode also shows a superior rate and cycle performances owing to the extended π-conjugated system, and the hierarchical pore bulk with large surface area.

Metal‐Tuned Acetylene Linkages in Hydrogen Substituted Graphdiyne Boosting the Electrochemical Oxygen Reduction

“…Two weak peaks for HsGDY/Cu 3 Pd‐750 and HsGDY‐750 at 2216 cm −1 correspond to acetylenic bonds (the section closed by the dotted red rectangle in Figure 2b), suggesting the formation of acetylene linkages between two ethynyl groups of 1,3,5‐Triethynylbenzene (TEB) monomer. All FT‐IR spectra and Raman spectra investigation results are in good line with that of pristine HsGDY (Figures S7 and S8, Supporting Information) and the previous reports 30,32. However, as for rGO‐supported Cu 3 Pd nanocomposites without HsGDY (rGO/Cu 3 Pd) obtained by annealing at 750 °C in N 2 atmosphere, no peak is observed at around 2210 cm −1 except for two peaks at 1376 and 1600 cm −1 .…”

“…As shown in Figure a and Figure S1 (Supporting Information), HsGDY in a spherical shape with the diameter of about 300 nm is successfully wrapped by thin GO nanosheets with the wrinkled texture, instead of laying on the surface of GO nanosheet. HsGDY carbon wrapped by GO nanosheet is confirmed by the X‐ray diffraction pattern (XRD, Figure S1d, Supporting Information) that reveals a characteristic carbon peak at about 21°, which is distinct from the peak position of graphene due to the interlayer spacing of 4.19 Å for HsGDY 30,32. This XRD result is well consistent with that of pristine HsGDY carbon (Figure S2, Supporting Information).…”

“…These results suggest the sandwich‐like rGO‐Cu 3 Pd‐HsGDY structure. A closer look at Cu 3 Pd nanoalloy and amorphous‐crystalline HsGDY in the HRTEM image exhibits the conformational fluctuation of HsGDY nanoparticles,32 and the clear crystal lattice with the lattice spacing of 0.217 nm (Figure 1d), corresponding to the parallel (111) plane of Cu 3 Pd alloy 33. EDS element mapping and EDS line scan profiles (Figure 1f) across an individual Cu 3 Pd nanoalloy show a rather homogenous distribution of Cu and Pd in the whole profile, indicative of the alloyed microstructure of Cu and Pd, which is in line with the XRD and ICP‐MS results.…”

Emerging Electrochemical Energy Applications of Graphdiyne

“…2 The size of the in-plane cavities in GDY can be accurately tuned for atomic-level selectivity via varying the terminal acetylenic groups of precursor. 3 Molecular engineering introduces heteroatoms and functional groups into GDY readily; thus, its intrinsic electronic structure (band gap), optical property, and surface energy are artificially tailorable. It performs with high mechanical modulus and stiffness, fulfilling diverse requirements for constructing composite materials.…”

Miniaturized Energy Storage Devices Based on Two‐Dimensional Materials

“…Two‐dimensional all‐carbon graphdiyne is composed of conjugated sp 2 ‐ and sp‐hybridized carbon atoms, and is known as the most stable allotrope of synthetic carbon diacetylene . Because of its special electronic structure and narrow band gap properties, graphdiyne has been explored for many electrochemical/photoelectrochemical applications, including LIBs/sodium‐ion batteries and SCs . In particular, due to triangular holes, large surface area, and rapid electrolyte ion diffusion of sp‐ and sp 2 ‐hybridized carbon atoms, graphdiyne should be advantageous in boosting specific power and energy densities for MESDs.…”