Watermelon-like multicore-shell Fe(PO3)2@carbon nanocapsule anode to construct an all iron phosphate-based sodium ion battery
Lu Yue, Jingyu Zhang, Meng Kong, Kai Li, Wenhui Zhang, Xiaotian Guo, Mengmeng Xiao, Feng Zhang, Huan Pang
Abstract
Rechargeable sodium ion battery (SIB) has attracted much attention recently. However, the deficiency of high-performance electrode materials limits its commercial development. Exploring new cost-effective, high safe electrode materials and full battery matching technology is an important direction of future research. In this work, a novel watermelon-like multicore-shell Fe(PO3)2@C nanocapsule anode material is designed via a facile and eco-friendly process for high performance SIB. Fe(PO3)2@C composite anode exhibits remarkable electrochemical performances for SIB, showing high sodium storage capacity (452 mAh·g−1 at 0.2 A·g−1), good rate (235 mAh·g−1 at 10 A·g−1), stable long-term cycling life (210 mAh·g−1 over 2,000 cycles under 5 A·g−1), and superior high-low temperature performance. Furthermore, a new type all iron-based phosphate full battery with high specific capacity is constructed, which can output initial capacity of 309 mAh·g−1 and a high energy density of 254, 107, and 82 Wh·kg−1 at the power density of 186, 917, and 1,640 W·kg−1 at room temperature. The exceptional performance of multicore-shell Fe(PO3)2@C nanocapsule structure can be ascribed to the large specific surface, good structure stability, high conductivity, as well as the multiple layer protection for superior electron/ion transportation.