Rational Construction of Yolk–Shell Bimetal-Modified Quinonyl-Rich Covalent Organic Polymers with Ultralong Lithium-Storage Mechanism

Abstract

Covalent organic polymers are attracting more and more attention for energy storage devices due to their lightweight, molecular viable design, stable structure, and environmental benignity. However, low charge-carrier mobility of pristine covalent organic materials is the main drawback for their application in lithium-ion batteries. Herein, a yolk−shell bimetal-modified quinonyl-rich covalent organic material, Co@2AQ-MnO 2 , has been designed and synthesized by in situ loading of petal-like nanosized MnO 2 and coordinating with Co centers, with the aim to improve the charge conductivity of the covalent organic polymer and activate its Li-storage sites. As investigated by in situ FT-IR, ex situ XPS, and electrochemical probing, the quinonyl-rich structure provides abundant redox sites (carbonyl groups and π electrons from the benzene ring) for lithium reaction, and the introduction of two types of metallic species promotes the charge transfer and facilitates more efficient usage of active energy-storage sites in Co@2AQ-MnO 2 . Thus, the Co@2AQ-MnO 2 electrode exhibits good cycling performance with large reversible capacity and excellent rate performance (1534.4 mA h g −1 after 200 cycles at 100 mA g −1 and 596.0 mA h g −1 after 1000 cycles at 1000 mA g −1 ).

Structure regulation induced high capacity and ultra-stable cycling of conjugated organic cathodes for Li-ion batteries

“…An obvious increase in capacity along with the Coulomb efficiency can be observed for the three cathode materials in the rst few cycles, which can be ascribed to the gradual stabilization of the electrode interface and the utilization of more activated redox sites. 37 Aer 200 cycles, the capacities of P(PTO-T2) and P(PTO-TT) remain as high as 144 and 155 mA h g −1 , respectively, indicating the good cycling performance of both materials. For P(PTO-T1), higher specic capacities of 187 mA h g −1 and 173 mA h g −1 are obtained at the second and 186 cycles, respectively.…”

Covalent organic frameworks as electrode materials for rechargeable metal‐ion batteries

“…Recently, a 2AQ‐MnO 2 composite has been prepared by introducing a petal‐like nanosized MnO 2 layer into the conjugated polymer of 2AQ (two ligands with active quinone groups), and then a Co@2AQ‐MnO 2 composite was prepared by coordinating with Co centers (Figure 8A). [ 131 ] Figure 8B–G displays the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the as‐obtained material. Clearly, after 2AQ was integrated with the nanosized petal‐like MnO 2 layer, both 2AQ‐MnO 2 and Co@2AQ‐MnO 2 displayed a unique yolk–shell morphology, whereas 2AQ displayed smooth nanospheres.…”

“…(I) Cycling performance of 2AQ, 2AQ‐MnO 2 , and Co@2AQ‐MnO 2 at 1000 mA g −1 . [ 131 ] Copyright 2022, American Chemical Society. SEM, scanning electron microscopy; TEM, transmission electron microscopy.…”

β‐Ketoenamine‐Linked Covalent Organic Framework with Co Intercalation: Improved Lithium‐Storage Properties and Mechanism for High‐Performance Lithium‐Organic Batteries

“…Organic electrode materials have become attractive alternative electrode materials and have been widely adopted in the field of lithium‐ion batteries recently [8–11] . Especially the metal‐organic framework (MOFs) [12,13] and covalent organic framework (COFs) [14,15] have attracted more attentions, due to their advantages of flexible design, low cost and environmental‐friendliness.…”

“…[6,7] Organic electrode materials have become attractive alternative electrode materials and have been widely adopted in the field of lithium-ion batteries recently. [8][9][10][11] Especially the metal-organic framework (MOFs) [12,13] and covalent organic framework (COFs) [14,15] have attracted more attentions, due to their advantages of flexible design, low cost and environmental-friendliness. Covalent organic framework (COF), as a kind of crystalline polymers assembled by covalent bonds through reversible reactions, exhibits high porosity with uniform nano-porous structure.…”