Linqu Luo1, Jianjun Song2, Longfei Song1, Hongchao Zhang1, Yicheng Bi3, Lei Liu4, Longwei Yin5, Fengyun Wang6, Guoxiu Wang7. 1. College of Physics and State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao, 266071, People's Republic of China. 2. College of Physics and State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao, 266071, People's Republic of China. jianjun.song@qdu.edu.cn. 3. College of Electromechanical Engineering, Qingdao University of Science and Technology, No. 99 Songling Road, Qingdao, 260061, Shandong, People's Republic of China. 4. School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao, 266590, People's Republic of China. 5. School of Materials Science and Engineering, Shandong University, Jinan, 250061, People's Republic of China. 6. College of Physics and State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao, 266071, People's Republic of China. fywang@qdu.edu.cn. 7. Centre for Clean Energy Technology, University of Technology Sydney, Broadway, Sydney, NSW, 2007, Australia. Guoxiu.Wang@uts.edu.au.
Abstract
Metallic Sn has provoked tremendous progress as an anode material for sodium-ion batteries (SIBs). However, Sn anodes suffer from a dramatic capacity fading, owing to pulverization induced by drastic volume expansion during cycling. Herein, a flexible three-dimensional (3D) hierarchical conductive network electrode is designed by constructing Sn quantum dots (QDs) encapsulated in one-dimensional N,S co-doped carbon nanofibers (NS-CNFs) sheathed within two-dimensional (2D) reduced graphene oxide (rGO) scrolls. In this ingenious strategy, 1D NS-CNFs are regarded as building blocks to prevent the aggregation and pulverization of Sn QDs during sodiation/desodiation, 2D rGO acts as electrical roads and "bridges" among NS-CNFs to improve the conductivity of the electrode and enlarge the contact area with electrolyte. Because of the unique structural merits, the flexible 3D hierarchical conductive network was directly used as binder- and current collector-free anode for SIBs, exhibiting ultra-long cycling life (373 mAh g-1 after 5000 cycles at 1 A g-1), and excellent high-rate capability (189 mAh g-1 at 10 A g-1). This work provides a facile and efficient engineering method to construct 3D hierarchical conductive electrodes for other flexible energy storage devices.
Metallic n class="Chemical">Sn has provoked tremendous progress as an anode material for sodium-ion batteries (SIBs). However, Sn anodes suffer from a dramatic capacity fading, owing to pulverization induced by drastic volume expansion during cycling. Herein, a flexible three-dimensional (3D) hierarchical conductive network electrode is designed by constructing Sn quantum dots (QDs) encapsulated in one-dimensional N,S co-doped carbon nanofibers (NS-CNFs) sheathed within two-dimensional (2D) reduced graphene oxide (rGO) scrolls. In this ingenious strategy, 1D NS-CNFs are regarded as building blocks to prevent the aggregation and pulverization of Sn QDs during sodiation/desodiation, 2D rGO acts as electrical roads and "bridges" among NS-CNFs to improve the conductivity of the electrode and enlarge the contact area with electrolyte. Because of the unique structural merits, the flexible 3D hierarchical conductive network was directly used as binder- and current collector-free anode for SIBs, exhibiting ultra-long cycling life (373 mAh g-1 after 5000 cycles at 1 A g-1), and excellent high-rate capability (189 mAh g-1 at 10 A g-1). This work provides a facile and efficient engineering method to construct 3D hierarchical conductive electrodes for other flexible energy storage devices.