Molecular grafting towards high-fraction active nanodots implanted in N-doped carbon for sodium dual-ion batteries

• Published in: National science review Vol. 8; no. 7; p. nwaa178
• Main Authors: Mu, Sainan, Liu, Qirong, Kidkhunthod, Pinit, Zhou, Xiaolong, Wang, Wenlou, Tang, Yongbing
• Format: Journal Article
• Language: English
• Published: China Oxford University Press 01.07.2021
• Subjects: N-doped carbon; molecular grafting; tin pyrophosphate; sodium-based dual-ion batteries; high-fraction active material
• ISSN: 2095-5138; 2053-714X; 2053-714X
• DOI: 10.1093/nsr/nwaa178

Abstract Sodium-based dual-ion batteries (Na-DIBs) show a promising potential for large-scale energy storage applications due to the merits of environmental friendliness and low cost. However, Na-DIBs are generally subject to poor rate capability and cycling stability for the lack of suitable anodes to accommodate large Na+ ions. Herein, we propose a molecular grafting strategy to in situ synthesize tin pyrophosphate nanodots implanted in N-doped carbon matrix (SnP2O7@N-C), which exhibits a high fraction of active SnP2O7 up to 95.6 wt% and a low content of N-doped carbon (4.4 wt%) as the conductive framework. As a result, this anode delivers a high specific capacity ∼400 mAh g−1 at 0.1 A g−1, excellent rate capability up to 5.0 A g−1 and excellent cycling stability with a capacity retention of 92% after 1200 cycles under a current density of 1.5 A g−1. Further, pairing this anode with an environmentally friendly KS6 graphite cathode yields a SnP2O7@N-C||KS6 Na-DIB, exhibiting an excellent rate capability up to 30 C, good fast-charge/slow-discharge performance and long-term cycling life with a capacity retention of ∼96% after 1000 cycles at 20 C. This study provides a feasible strategy to develop high-performance anodes with high-fraction active materials for Na-based energy storage applications. High-fraction active material (95.6 wt%) implanted in nitrogen-doped carbon matrix is designed for sodium-based dual-ion batteries with superior rate performance and long-term cycling life.