Lithium Accommodation in a Redox‐Active Covalent Triazine Framework for High Areal Capacity and Fast‐Charging Lithium‐Ion Batteries

Abstract

The synthesis of a new type of redox‐active covalent triazine framework (rCTF) material, which is promising as an anode for Li‐ion batteries, is reported. After activation, it has a capacity up to ≈1190 mAh g−1 at 0.5C with a current density of 300 mA g−1 and a high cycling stability of over 1000 discharge/charge cycles with a stable Coulombic efficiency in an rCTF/Li half‐cell. This rCTF has a high rate performance, and at a charging rate of 20C with a current density of 12 A g−1 and it functions well for over 1000 discharge/charge cycles with a reversible capacity of over 500 mAh g−1. By electrochemical analysis and theoretical calculations, it is found that its lithium‐storage mechanism involves multi‐electron redox‐reactions at anthraquinone, triazine, and benzene rings by the accommodation of Li. The structural features and progressively increased structural disorder of the rCTF increase the kinetics of infiltration and significantly shortens the activation period, yielding fast‐charging Li‐ion half and full cells even at a high capacity loading.

Conjugated Microporous Polymers with Bipolar and Double Redox‐Active Centers for High‐Performance Dual‐Ion, Organic Symmetric Battery

“…To further confirm the preferred active site, the binding energies of two active sites from CuPcNA-CMP bonded with Li ion are calculated (Figure 5b; Figure S19, Supporting Information). [49][50][51] The binding energy between site 1 and Li ion is −3.51 eV, which is lower than that between site 2 and Li ion (−3.36 eV), indicating the preferred lithium insertion in CO group rather than the Pc macrocycle. Previous reports have demonstrated the preferred active sites from CO group of aromatic carbonyl, but four CO groups are utilized under a deepdischarge below 1.5 V. [52,53] More specifically, only two CO groups can be utilized above 1.5 V, in which two CO groups at the diagonal positions can capture Li ion and then the conjugated structure between perylene and two CO groups can be formed.…”

Double‐Shelled Hollow SiO2@N‐C Nanofiber Boosts the Lithium Storage Performance of [PMo12O40]3−

“…[46][47][48][49] In order to clarify the reason for the unusual "negative fading" phenomenon, GCD profiles of the hollow PMo 12 À SiO 2 @NÀ C electrode at different cycles were plotted and the partial discharge capacity within a specific potential regime at different cycles were analyzed (Figure S11). [60] With the increase of the cycle number, the corresponding GCD curves of PMo 12 À SiO 2 @NÀ C changed as well (Figure S11a) and the calculated partial capacity within 0.5-2.0 V increased significantly (Figure S11b). Since the partial discharge capacity within 0.5-2.0 V corresponded only to PMo 12 , the result proved that PMo 12 was responsible for the "negative fading" phenomenon.…”

Regulating Steric Hindrance in Redox‐Active Porous Organic Frameworks Achieves Enhanced Sodium Storage Performance

“…Interestingly, the AP-1 electrode shows a gradual activation process, which can be attributed to the gradual activation of deeply buried active sites inside the porous architecture for Na storage. [14] When we tested the cycling performance at the current density of 0.1 A g −1 , fewer cycles are needed to realized this activation process, due to the fact that the small current is more conducive to the full reaction of the active materials (Figure S12, Supporting Information). After cycling to the point III, the electrode displays average reversible capacities of 372, 285, and 205 mAh g −1 at current densities of 0.1, 0.4, and 3.0 A g −1 , respectively (Figure 2b).…”

“…[11] For redox-active polymers, alternatively, regulating structural morphology to facilitate the redox dynamics has been developed as an efficient method to enhance lithium (Li) storage on functionalized C6-benzene rings because of the superlithiation. [12][13][14] However, compared to Li ions, the insertion of Na ions requires much faster kinetics owing to its larger ion radius and weaker chemical binding to a given substrate. [15,16] As such, it remains a challenge to achieve fast diffusion rates and strong electrochemical affinities of Na ions simultaneously within polymeric skeletons.…”