ABSTRACT The imbalance between energy density and power density largely limits lithium-ion hybrid capacitor (Li-HEC) advance for various applications. In this work, we report on the construction of a binder-free and porous electrode, which is self-standing T-Nb2O5/graphene hybrid aerogels, as Li-intercalating pseudocapacitive electrodes of Li-HECs. The aerogels, with ultrafine T-Nb2O5 nanorods (10 ~ 40 nm) uniformly growing on the surface of graphene, feature short lithium-ion transport length, large specific surface area, 3D porous structure and good conductivity, and thus demonstrate both reversible specific capacity (~190 mAh/g at 1 C) and good rate capability (~90 mAh/g at 20 C). Most importantly, Li-HEC devices using activated graphene foam as binder-free cathode can achieve excellent energy densities (53 and 19.7 Wh/kg at power of 355 and 2009 W/kg, respectively) and remarkable cycling performance (capacitance retention of 89% after 3000 cycles), benefitting from good matching between cathode and anode as well as their fascinating microstructures.

中文翻译：

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Nb2O5/石墨烯混合气凝胶作为锂离子电容器聚合物无粘合剂电极的设计

摘要 能量密度和功率密度之间的不平衡在很大程度上限制了锂离子混合电容器 (Li-HEC) 在各种应用中的发展。在这项工作中，我们报告了无粘合剂多孔电极的构建，该电极是自立式 T-Nb2O5/石墨烯混合气凝胶，作为 Li-HEC 的嵌锂赝电容电极。该气凝胶具有均匀生长在石墨烯表面的超细 T-Nb2O5 纳米棒 (10 ~ 40 nm)，具有锂离子传输长度短、比表面积大、3D 多孔结构和良好的导电性，从而表现出可逆的比容量（~190 mAh/g at 1 C）和良好的倍率性能（~90 mAh/g at 20 C）。最重要的是，使用活性石墨烯泡沫作为无粘合剂正极的 Li-HEC 器件可以实现出色的能量密度（53 和 19.