Superlithiation Performance of Covalent Triazine Frameworks as Anodes in Lithium-Ion Batteries

Abstract

Organics with the merit of renewability have been viewed as the promising alternative of inorganic electrode materials in lithium-ion batteries, but most of them display inferior performance due to the sluggish ion/electron diffusion and the potential dissolution in aprotic electrolytes. Here, covalent triazine frameworks (CTFs-1), full of vertical pores and layered spaces for Li+ transfer, have been synthesized with p-dicyanobenzene as the monomer by a facile two-step method including a prepolymerization with CF3SO3H as the catalyst and deep polymerization in molten ZnCl2. CTFs-1-400, obtained at the deep polymerization temperature of 400 °C, exhibits the superlithiation property with the specific capacities of 1626 mA h g–1 at 25 °C and 1913 mA h g–1 at 45 °C at 100 mA g–1, indicating the formation of Li6C6/Li6C3N3 in the reduction process. Electrochemical analysis and density functional theory calculation indicate that the ultrahigh capacity is mainly contributed by the capacitance of micropores and the redox capacity of benzene and triazine rings. Moreover, CTFs-1-400 displays the specific capacity of 740 mA h g–1 for 1000 cycles at 1 A g–1 with almost no capacity fading.

Superlithiation Performance of Pyridinium Polymerized Ionic Liquids with Fast Li+ Diffusion Kinetics as Anode Materials for Lithium‐Ion Battery

“…In the images of high‐resolution transmission electron microscope (HRTEM), PILs‐Py‐300 exhibited rock surfaces, which resulted from imperfect polymerization due to relatively low polymerization temperature ( Figure a). [ 9 ] PILs‐Py‐400 and PILs‐Py‐500 presented quite regular and laminar morphology with abundant micropores, which can be observed as white spots at the nanoscale meter (Figure 3b,c). Besides, the energy dispersive spectrometer (EDS) confirmed the existence of Cl element in PILs‐Py‐300/400/500 (Figure S5, Supporting Information).…”

“…[3,5,6] Typically, to enhance Li + -storage in LIBs, the efforts on electrode materials mainly focused on organic materials with "Superlithiation" performance, which incorporated multiple, stable, and reversible redox groups in the conjugated skeleton (such as benzene rings and triazine rings), forming Li 6 C 6 or Li 6 C 3 N 3 . [7][8][9][10][11][12][13] For these redox organic materials, there still have some intrinsic issues needed to be overcome, including insufficient ion diffusion kinetics, which leads to not only a low capacity but also unsatisfied rate capacity and cycling performance. [14][15][16][17][18][19] In theory, the positively charged skeleton facilitates Li + fast migration in the conjugated chains, benefiting for redox PILs to realize the superlithiation performance, which is very promising to solve the problem of the slow ion diffusion kinetics in organic electrode materials.…”

Emerging covalent triazine framework-based nanomaterials for electrochemical energy storage and conversion

“…Distinctively, Dai et al synthesized CTF-1 through a pre-polymerization step with CF 3 SO 3 H as the catalyst, followed by a polymerization step in molten ZnCl 2 . 126 The attained CTF-1 displayed a super-lithiation performance, and both the triazine rings and benzene rings can store Li + ions in the form of Li 6 C 6 or Li 6 C 3 N 3 . Remarkably, the optimal CTF-1-400 showed a specific capacity of 740 mA h g À1 for 1000 cycles at 1 A g À1 with negligible capacity deterioration.…”

Small Molecule Azaacene as an Anode Material for Lithium-Ion Batteries

“…This led to the development of additional azaacene superlithiation materials, including the subject of this work. More recently, superlithiation has been reported in networks comprising triazines, , naphthalimides, and aramids, thus showing the diversity of structures that can lead to ultra-high capacities.…”