College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China.
Dongying Cospowers Technology Limited Company, Dongying, 257091 Shandong, China.
Inorg Chem. 2023 Jun 12;62(23):9099-9110. doi: 10.1021/acs.inorgchem.3c00948. Epub 2023 May 25.
NaFe(PO)(PO) (NFPP) is an attractive candidate for Na batteries (SIBs) and Li batteries (LIBs). However, the real implementation of NFPP has been critically restrained by the inferior intrinsic electronic conductivity. Herein, carbon-coated mesoporous NFPP, obtained via freeze drying and heat treatment, demonstrates highly reversible insertion/extraction of Na/Li. Mechanically, the electronic transmission and structural stabilities of NFPP are significantly enhanced by the graphitized carbon coating layer. Chemically, the porous nanosized structure shortens Na/Li diffusion paths and increases the contact area between the electrolyte and NFPP, ultimately rendering fast ion diffusion. Greatly, long-lasting cyclability (88.5% capacity retention for over 5000 cycles), decent thermal stability at 60 °C, and impressive electrochemical performances are demonstrated in LIBs. The insertion/extraction mechanisms of NFPP in both SIBs and LIBs are systematically investigated, confirming its small volume expansion and high reversibility. The superior electrochemical performances and the insertion/extraction mechanism investigation confirm the feasibility of utilizing NFPP as a cathode material for Na/Li batteries.
磷酸铁（磷）（NFPP）是一种有吸引力的候选钠离子电池（SIBs）和锂离子电池（LIBs）。然而，NFPP 的实际应用受到较差的本征电子电导率的严重限制。本文通过冷冻干燥和热处理得到了碳包覆介孔 NFPP，表现出高度可逆的钠离子/锂离子的嵌入/脱出。在机械方面，石墨化碳涂层显著提高了 NFPP 的电子传输和结构稳定性。在化学方面，多孔纳米结构缩短了钠离子/锂离子的扩散路径，增加了电解质与 NFPP 的接触面积，最终实现了快速的离子扩散。在 LIBs 中，其表现出了优异的循环稳定性（超过 5000 次循环，容量保持率为 88.5%）、良好的 60°C 热稳定性和出色的电化学性能。系统地研究了 NFPP 在 SIBs 和 LIBs 中的嵌入/脱出机制，证实了其小的体积膨胀和高的可逆性。优异的电化学性能和嵌入/脱出机制的研究证实了 NFPP 作为钠离子/锂离子电池正极材料的可行性。
