A donor–acceptor (D–A) conjugated polymer for fast storage of anions

Abstract

Organic electrode materials have attracted a lot interest in batteries in recent years. However, most of them still suffer from low performance such as low electrode potential, slow reaction kinetics, and short cycle life. In this work, we report a strategy of fabricating donor–acceptor (D–A) conjugated polymers for facilitating the charge transfer and therefore accelerating the reaction kinetics by using the copolymer (p‐TTPZ) of dihydrophenazine (PZ) and thianthrene (TT) as a proof‐of‐concept. The D–A conjugated polymer as p‐type cathode could store anions and exhibited high discharge voltages (two plateaus at 3.82 V, 3.16 V respectively), a reversible capacity of 152 mAh g−1 at 0.1 A g−1, excellent rate performance with a high capacity of 124.2 mAh g−1 at 10 A g−1 (≈50 C) and remarkable cyclability. The performance, especially the rate capability was much higher than that of its counterpart homopolymers without D–A structure. As a result, the p‐TTPZ//graphite full cells showed a high output voltage (3.26 V), a discharge specific capacity of 139.1 mAh g−1 at 0.05 A g−1 and excellent rate performance. This work provides a novel strategy for developing high performance organic electrode materials through molecular design and will pave a way towards high energy density organic batteries.

Engineering the Interfacial Compatibility of a Small-Molecule Quinone Cathode toward Stable Quasi-Solid-State Lithium-Organic Batteries

“…In addition, the use of inorganic cathode materials also suffers from challenges such as structural and chemical instabilities, limited resources, high environmental footprint, and high-energy production. − In contrast, organic cathode materials have received increasing attention in view of their low environmental footprint, cost-effective features, and resource sustainability. In particular, organic small molecules are readily available from nature and have high theoretical specific capacity; unfortunately, their dissolution in electrolytes leads to poor cycling stability. − To solve the dissolution problem, polymerization or hybridization has been made, which may suffer from defects such as extra synthesis costs and additional inactive components. In fact, the structure diversity of small organic molecules can confer them high interfacial compatibility with PEs, thus, constructing quasi-solid-state lithium-organic batteries (QSSLOBs) is a wise and win–win strategy.…”