Organic compounds with high theoretical capacity, tunable redox potentials and rich structural chemistry are considered as promising electrode materials for sodium-ion batteries (SIBs). However, organic electrode materials suffer from low electronic conductivity and low structural stability, hindering their practical applications. Thiophene compounds have been well considered in the design of photoelectric materials with improved charge transfer properties. It is envisaged that electron-transfer capability is also essential in addressing the issues of organic electrode materials for SIBs. Herein, sodium thieno[3,2-b]thiophene-2,5-dicarboxylate (STTDC), an organic compound with high electron transfer capability is designed and synthesized. When employed as an electrode material for SIBs, remarkably high electrochemical performance, including large reversible capacity, high rate capability and excellent stability was achieved. A large specific discharge capacity of 430 mA h g⁻¹ is delivered at a current density of 50 mA g⁻¹. A high reversible capacity of approximately 288 mA h g⁻¹ is retained after 4000 cycles at a high current density of 2.0 A g⁻¹. The present work sheds new light on the design of high-performance organic electrode materials.

中文翻译：

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噻吩衍生物作为高性能钠离子电池的电极材料

具有高理论容量，可调节的氧化还原电势和丰富的结构化学的有机化合物被认为是钠离子电池（SIB）的有前途的电极材料。然而，有机电极材料具有低电导率和低结构稳定性，从而阻碍了其实际应用。噻吩化合物已经在具有改善的电荷转移性能的光电材料的设计中被充分考虑。设想电子转移能力在解决用于SIB的有机电极材料的问题中也是必不可少的。在此，硫代硫酸钠[3,2- b设计合成了具有高电子转移能力的有机化合物二噻吩-2,5-二羧酸酯（STTDC）。当用作SIB的电极材料时，获得了非常高的电化学性能，包括大的可逆容量，高倍率容量和优异的稳定性。在50 mA g ^-1的电流密度下可提供430 mA hg ^-1的大比放电容量。4000次循环后，在2.0 A g ^-1的高电流密度下，保持了约288 mA hg ^-1的高可逆容量。本工作为高性能有机电极材料的设计提供了新的思路。