Na₃V₂(PO₄)₃ (NVP) with an open NASICON structure has drawn worldwide attention as a potential cathode material for sodium-ion batteries (SIBs) owing to its high theoretical capacity. However, the inherently poor electronic conductivity of NVP severely restricts its electrochemical performance, particularly for rate capability and long cycle performance. Herein, high performance NVP/C cathode (denoted as NVP/C-T) is demonstrated by designing and synthesizing three-dimensional (3D) hierarchical porous NVP architecture via a facile hydrothermal technique. In this hierarchical porous structure, ultrathin NVP nanosheets capped with in-situ carbon layers are interlinked to form hierarchical pores, convenient nanochannels and 3D conductive carbon framework. This delicate structure not only provides adequate void for the intimate contact between electrode/electrolyte, shortens ionic diffusion distances, ensures the ultrafast electron transfer but also strengthens the structural stability of electrode material. The as-prepared NVP/C-T cathode exhibits a high reversible initial capacity (114.8 mAh g⁻¹ at 1 C approaching the theoretical capacity), excellent rate performance (89.3 mAh g⁻¹ at 60 C and 73.2 mAh g⁻¹ at 80 C) and long life span (93.3 mAh g⁻¹ after 8000 cycles at 20 C). In addition, the electrochemical properties of symmetric full cell constructed with NVP/C-T/ NVP/C-T are also studied and high initial charge capacity (101.8 mAh g⁻¹ at 0.25 C) and high stability (70.1 mAh g⁻¹ at 2 C after 200 cycles) are achieved. Significantly, the design of the 3D hierarchical porous [email protected] strategy and scalable synthesis method may pave a way to develop high performance SIBs.

Na ₃ V ₂（PO ₄）₃具有开放NASICON结构的NVP（NVP）由于其较高的理论容量而作为钠离子电池（SIB）的潜在阴极材料引起了全世界的关注。但是，NVP固有的较差的电导率严重限制了其电化学性能，特别是对于速率性能和长循环性能。在此，通过设计和合成通过简便的水热技术的三维（3D）分层多孔NVP体系结构，展示了高性能NVP / C阴极（表示为NVP / CT）。在这种分层的多孔结构中，覆盖有原位碳层的超薄NVP纳米片相互连接以形成分层的孔，便捷的纳米通道和3D导电碳骨架。这种精致的结构不仅为电极/电解质之间的紧密接触提供了足够的空隙，缩短了离子扩散距离，确保了超快的电子转移，还增强了电极材料的结构稳定性。所制备的NVP / CT阴极具有很高的可逆初始容量（114.8 mAh g1 C时的^-1接近理论容量），出色的速率性能（60 C时为89.3 mAh g ^-1和80 C时为73.2 mAh g ^-1）和长寿命（20 C 8000次循环后为93.3 mAh g ^-1） 。另外，还研究了用NVP / CT / NVP / CT构造的对称全电池的电化学性能，并具有较高的初始充电容量（0.25 C时为101.8 mAh g ^-1）和较高的稳定性（2 C后在7 C下为70.1 mAh g ^-1）。达到200个循环）。重要的是，3D分层多孔[受电子邮件保护]策略的设计和可扩展的综合方法可能为开发高性能SIB铺平道路。