Zhang Erjin, Jia Xinxin, Wang Bin, Wang Jue, Yu Xinzhi, Lu Bingan
School of Physics and Electronics State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan Provincial Key Laboratory of Multi-Electron Based Energy Storage Devices Hunan University Changsha 410082 P. R. China.
Physics and Electronic Engineering Department Xinxiang University Xinxiang 453003 P. R. China.
Adv Sci (Weinh). 2020 Jun 17;7(15):2000470. doi: 10.1002/advs.202000470. eCollection 2020 Aug.
Carbonaceous materials, especially with graphite-layers structure, as anode for potassium-ion batteries (PIBs), are the footstone for industrialization of PIBs. However, carbonaceous materials with graphite-layers structure usually suffer from poor cycle life and inferior stability, not to mention freestanding and flexible PIBs. Here, a freestanding and flexible 3D hybrid architecture by introducing carbon dots on the reduced graphene oxide surface (CDs@rGO) is synthesized as high performance PIBs anode. The CDs@rGO paper has efficient electron and ion transfer channels due to its unique structure, thus enhancing reaction kinetics. In addition, the CDs provide abundant defects and oxygen-containing functional groups, which can improve the electrochemical performance. This freestanding and flexible anode exhibits the high capacity of 310 mAh g at 100 mA g, ultra-long cycle life (840 cycles with a capacity of 244 mAh g at 200 mA g), and excellent rate performance (undergo six consecutive currents changing from 100 to 500 mA g, high capacity 185 mAh g at 500 mA g), outperforming many existing carbonaceous PIB anodes. The results may provide a starting point for high-performance freestanding and flexible PIBs and promote the rapid development of next-generation flexible batteries.
含碳材料，尤其是具有石墨层结构的材料，作为钾离子电池（PIBs）的阳极，是PIBs产业化的基石。然而，具有石墨层结构的含碳材料通常循环寿命较差且稳定性欠佳，更不用说独立式和柔性PIBs了。在此，通过在还原氧化石墨烯表面引入碳点（CDs@rGO）合成了一种独立式柔性三维混合结构，作为高性能PIBs阳极。CDs@rGO纸因其独特结构具有高效的电子和离子传输通道，从而增强了反应动力学。此外，碳点提供了丰富的缺陷和含氧官能团，可改善电化学性能。这种独立式柔性阳极在100 mA g下展现出310 mAh g的高容量、超长循环寿命（在200 mA g下循环840次，容量为244 mAh g）以及优异的倍率性能（连续经历六次从100到500 mA g的电流变化，在500 mA g下高容量为185 mAh g），优于许多现有的含碳PIBs阳极。这些结果可能为高性能独立式和柔性PIBs提供一个起点，并推动下一代柔性电池的快速发展。
