Na₄Fe₃(PO₄)₂P₂O₇ (NFPP) is expected to be a promising cathode material for sodium ion batteries (SIBs) applied to large-scale energy storage systems owing to its abundant resource and low cost of the raw materials. However, the currently reported methods for preparing NFPP either cannot be applied to mass-production on a large scale because of their high energy consumption, or result in the production of NFPP materials that have poor electrochemical performance. Herein, we prepared a hierarchical nitrogen-carbon-coated NFPP nanoflake by a facile and easily scalable solid-phase ball milling method, in which oleic acid as the surfactant and carbon source. The formation mechanism of this hierarchical open structure constructed by uniform nano-flakes was investigated by a heating-rate controlled experiment, which indicated that heating rates play an important role in morphology and structure of the final products. When used as a cathode material, the present NFPP nano-flakes composites are able to operate in a wide temperature range (-20∼50°C) and, can provide specific capacity of 129 mAh g^-1 at 0.1C, with excellent cycling stability (81% capacity retention at 10C after 1500 cycles) at 25°C. Furthermore, the NFPP cathode is coupled with the MoS₂ anode (MoS₂/rGO) to assemble the sodium ion full battery, it exhibits outstanding rate/cycling performances. The present work provides a method of preparing NFPP electrode materials with good performance for s SIBs, which can be easily amplified production.

Na ₄ Fe ₃ (PO ₄ ) ₂ P ₂ O ₇（NFPP）由于其丰富的资源和低廉的原材料成本，有望成为应用于大规模储能系统的钠离子电池（SIB）的有前途的正极材料。然而，目前报道的制备NFPP的方法要么因能耗高而无法大规模大规模生产，要么导致生产的NFPP材料电化学性能较差。在此，我们通过一种简便且易于扩展的固相球磨法制备了一种分级氮碳包覆的NFPP纳米片，其中油酸作为表面活性剂和碳源。通过加热速率控制实验研究了这种由均匀纳米薄片构成的分层开放结构的形成机制，这表明加热速率对最终产品的形态和结构起着重要作用。当用作正极材料时，目前的 NFPP 纳米薄片复合材料能够在很宽的温度范围（-20∼50°C）下工作，并且可以提供 129 mAh g 的比容量^{在 0.1C 时为-1}，在 25°C 时具有出色的循环稳定性（10C 下 1500 次循环后容量保持率为 81%）。此外，NFPP正极与MoS ₂负极（MoS ₂ /rGO）耦合组装成钠离子全电池，具有出色的倍率/循环性能。本工作提供了一种制备具有良好性能的 s SIBs NFPP 电极材料的方法，该方法易于放大生产。