In Situ Electrospinning Synthesis of N‐Doped C Nanofibers with Uniform Embedding of Mn Doped MFe<sub>1−</sub><i><sub>x</sub></i>Mn<i><sub>x</sub></i>PO<sub>4</sub> (M = Li, Na) as a High Performance Cathode for Lithium/Sodium‐Ion Batteries
Wenyan Chen, Donghui Xu, Yuancheng Chen, Tang Tang, Shaojie Kuang, Haikuo Fu, Wuyi Zhou, Xiaoyuan Yu
Abstract
Abstract Using polyvinyl alcohol and N‐rich polyacrylonitrile as carbon sources, uniform MFe 1– x Mn x PO 4 (M = Li, Na)/N‐doped C nanofibers are synthesized by sol–gel pretreatment and an electrospinning method followed by calcination. The as‐prepared nanofibers exhibit a 3D homogenous network with uniform distribution of MFe 1− x Mn x PO 4 nanoparticles. The lattice distorts after Mn‐doping without altering the original crystalline structure, increasing conductivity and enhancing the efficiency of Li + /Na + diffusion. When applied for lithium ion batteries, the optimized LiFe 0.8 Mn 0.2 PO 4 /C nanofibers deliver a considerable initial capacity of 169.9 mAh g −1 with coulombic efficiency of 92.4%. It also displays the excellent cycling stability with reversible capacity of 160 mAh g −1 after 200 cycles at 0.1 C and high rate performances with the specific capacity of 93 mAh g −1 at 5 C. Furthermore, NaFe x Mn 1− x PO 4 /N‐doped C nanofibers are also synthesized by the same method for sodium‐ion batteries, which exhibit an initial capacity of 134 mAh g −1 and specific capacity of 106 mAh g −1 at 0.1 C and 90 mAh g −1 at 1 C after 200 cycles. Owing to the facile fabrication process, these nanofibers are promising cathodes for lithium/sodium ion batteries with excellent electrochemical performances.