Synergistic Effect of Hydrogen Bonding and π–π Stacking Enables Long Cycle Life in Organic Electrode Materials

Abstract

Small-molecule organic compounds have emerged as attractive candidates for energy storage in lithium-ion batteries because of their sustainability and modularity. To develop generalizable design principles for organic electrode materials (OEMs), we investigated the correlation between electrochemical performance and addition of functional groups that promote synergistic hydrogen bonding and π−π stacking using a series of quinone-fused aza-phenazines (QAPs) with different hydrogen bonding donor/acceptor arrays. The QAP containing the most hydrogen bonding groups (3) exhibits the best performance with discharge capacities of 145 mAh g −1 at 2C and with 82% capacity retention over 1000 cycles. The performance of 3 is attributed to the strategically incorporated hydrogen bonding groups, which facilitate strong intermolecular interactions and a tightly packed 2D structure. The intermolecular interaction strength was evaluated using variable temperature 1D 1 H NMR and 2D 1 H− 1 H NOESY (nuclear Overhauser effect spectroscopy), offering a new strategy to help understand and predict the performance of OEMs with hydrogen bonding motifs.

Two‐Dimensional Organic Supramolecule via Hydrogen Bonding and π–π Stacking for Ultrahigh Capacity and Long‐Life Aqueous Zinc–Organic Batteries

“…The bond lengths of hydrogen bond between hydrogen atom in CÀ H and the oxygen atom in carbonyl group were about 2.005 Å and 2.146 Å, which are consistent with the typical hydrogen bonds in the literature. [36,47,48] The existence of hydrogen bonding in HATNQ molecule was further demonstrated by FTIR (Figure S1) and theoretical calculation (Figure S7). In addition, the HATNQ molecules are tightly packed with the neighbour HATNQ in adjacent supramolecular sheets through a displaced layer-by-layer π-π interaction and the corresponding interfacial spacing is about 3.26 Å, which is agreement with the result of HRTEM (Figure 1e).…”

Optimization of Monomer Molecular Structure for Polymer Electrodes Fabricated through in‐situ Electro‐Polymerization Strategy

“…Nonetheless, they often suffer from severe dissolution in organic electrolytes and low electrical conductivity, leading to fast capacity fading and inferior rate performance [8,9] . To date, many methods have been adopted to alleviate the dissolution problem, including (1) the surface coating (Al 2 O 3 ) via atomic layer deposition, [10] (2) adding selectively permeable membrane, [11–13] (3) using solid‐state or high‐concentration electrolytes, [14,15] (4) encapsulating the active materials into microporous carbon scaffold (such as CMK‐3), [16] (5) using reasonable molecular design, [17] salification, [18] or polymerization, [19–22] and so on [23,24] . Among them, constructing polymers containing redox‐active units have been proved to be an effective approach, which could efficaciously inhibit the dissolution of redox‐active small molecules.…”

Surpassing the Redox Potential Limit of Organic Cathode Materials via Extended p−π Conjugation of Dioxin

“…However, the weak intermolecular forces of DpD molecules make it easy to dissolve in the electrolyte. Expanding the conjugate structure to enhance π–π stacking interactions can increase the electron transfer between adjacent charge-storage units and prevent the initial dissolution of electrode materials in the solvent . On the basis of the above consideration, a kind of tetraoxapentacene (TOP) motif is proposed (Figure a), which possesses four oxygen atoms bridged by the benzene center.…”