From Micropores to Ultra-micropores inside Hard Carbon: Toward Enhanced Capacity in Room-/Low-Temperature Sodium-Ion Storage

Nano-Micro Letters

Kexin Zhang¹  Ruqiang Zou¹  Xu Lian²  Xiaowei Wang²  Kian Ping Loh²  Wenrui Dai³  Ming Lin⁴  Jinlin Yang⁵  Wei Chen⁶  Quan-Hong Yang⁷  Weichao Zhang⁸  Xinhang Cui⁹ 

[1] Beijing Key Laboratory for Theory and Technology of Advanced Battery Materials, Department of Materials Science and Engineering, College of Engineering, Peking University, 100871, Beijing, People’s Republic of China;Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore;Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore;National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Suzhou, Jiangsu, China;Institute of Materials Research and Engineering (IMRE), Agency of Science, Technology, and Research (A*STAR), 3 Research Link, 117602, Singapore, Singapore;Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, 350207, Fuzhou, People’s Republic of China;Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore;National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Suzhou, Jiangsu, China;Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, 350207, Fuzhou, People’s Republic of China;Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore;National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Suzhou, Jiangsu, China;Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore, Singapore;Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, 350207, Fuzhou, People’s Republic of China;Nanoyang Group, State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, 300350, Tianjin, People’s Republic of China;Nanoyang Group, State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, 300350, Tianjin, People’s Republic of China;National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Suzhou, Jiangsu, China;Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore, Singapore;

关键词: Carbon anode;    Ultra-micropores;    Extra sodium-ion storage sites;    Low-voltage capacity;    High areal capacity;   

DOI  :  10.1007/s40820-020-00587-y

来源: Springer

【 摘 要 】

tsHard-carbon anode dominated with ultra-micropores (< 0.5 nm) was synthesized for sodium-ion batteries via a molten diffusion–carbonization method.The ultra-micropores dominated carbon anode displays an enhanced capacity, which originates from the extra sodium-ion storage sites of the designed ultra-micropores.The thick electrode (~ 19 mg cm−2) with a high areal capacity of 6.14 mAh cm−2 displays an ultrahigh cycling stability and an outstanding low-temperature performance.Abstract Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries (SIBs). Ultra-micropores (< 0.5 nm) of hard carbon can function as ionic sieves to reduce the diffusion of slovated Na+ but allow the entrance of naked Na+ into the pores, which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics. Herein, a molten diffusion–carbonization method is proposed to transform the micropores (> 1 nm) inside carbon into ultra-micropores (< 0.5 nm). Consequently, the designed carbon anode displays an enhanced capacity of 346 mAh g−1 at 30 mA g−1 with a high ICE value of ~ 80.6% and most of the capacity (~ 90%) is below 1 V. Moreover, the high-loading electrode (~ 19 mg cm−2) exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm−2 at 25 °C and 5.32 mAh cm−2 at − 20 °C. Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results, the designed ultra-micropores provide the extra Na+ storage sites, which mainly contributes to the enhanced capacity. This proposed strategy shows a good potential for the development of high-performance SIBs.

【 授权许可】

CC BY