A Nitro-Rich Small-Molecule-Based Organic Cathode Material for Effective Rechargeable Lithium Batteries

Organic cathode materials have attracted extensive research interest for rechargeable lithium-ion batteries (LIBs) because of their diverse structures and tunable properties. However, the preparation of organic cathode materials with high capacities, long cycling life, and high energy densities still remains a big challenge. To address these issues, we designed and synthesized a novel multinitro-decorated organic small molecule, N4,N4′′-bis­(2,4-dinitrophenyl)-5′-(4-((2,4-dinitrophenyl)­amino)­phenyl)-[1,1′:3′,1′′-terphenyl]-4,4′′-diamine (TAPB-6NO2), where the unique electronic character of nitro group should enable TAPB-6NO2 to be a promising cathode candidate for LIBs. We found that the introduction of multiple nitro groups could efficiently reduce the solubility of TAPB-6NO2 in organic electrolytes, resulting in a high specific capacity of around 180 mAh g–1 and stable cycling with a capacity retention of 91% after 1100 cycles at 1000 mA g–1. This work suggests that attaching multiple nitro groups on a small molecule is an effective approach to construct high-performance organic cathode materials for stable and sustainable rechargeable LIBs.有机正极材料因结构多样、性能可调控，在可充电锂离子电池（LIBs）领域受到广泛研究关注。不过，制备兼具高容量、长循环寿命与高能量密度的有机正极材料仍是一大挑战。为解决上述问题，我们设计并合成了一种新型多硝基修饰有机小分子：N4,N4′′-双(2,4-二硝基苯基)-5′-(4-((2,4-二硝基苯基)氨基)苯基)-[1,1′:3′,1′′-三联苯]-4,4′′-二胺（TAPB-6NO2）。硝基独特的电子特性赋予TAPB-6NO2作为锂离子电池正极候选材料的应用潜力。研究发现，引入多个硝基可有效降低TAPB-6NO2在有机电解液中的溶解度，使其实现约180 mAh g–1的高比容量，且在1000 mA g–1的电流密度下循环1100次后容量保持率仍达91%，循环性能稳定。本研究表明，在小分子上接枝多个硝基是构建高性能、稳定可持续的可充电锂离子电池有机正极材料的有效途径。