Polyanion-type cathode materials have grown in leaps and bounds and become one of the promising candidates for metal-ion batteries since the successful case of LiFePO₄ in lithium-ion batteries, which own stable crystal structure, high thermal stability, good ionic conductivity, adjustable voltage and chemical composition. However, further exploration is requisite, such as, the change of crystal/electronic structure, reaction mechanism, and structure evolution during charge/discharge processes, which results from variety of crystal types and redox centers, anion and cationic doping/substitution, as well as transition metal ion migration in polyanion-type materials. In this review, we focus on the advanced characterization techniques referred in polyanion-type cathode materials of sodium-ion batteries, mainly consist of the structure-related, morphology-related, composition-related techniques and in-situ/operando techniques during charge/discharge processes. The respective detection mechanisms, scope of application, information available and limitations of each technique are discussed in detail, and the latest developments of these characterization techniques used in polyanion-type materials are summarized. Advanced characterization techniques play a crucial role in understanding the reaction mechanisms of electrode materials, and can provide an important guiding principle for designing high-performance polyanion-type cathode materials and further optimizing the battery systems of sodium-ion batteries.

_{自LiFePO 4}的成功案例以来，聚阴离子型正极材料得到了突飞猛进的发展，成为金属离子电池最有前途的候选材料之一在锂离子电池中，其晶体结构稳定，热稳定性高，离子导电性好，电压和化学成分可调。然而，还需要进一步的探索，例如充放电过程中晶体/电子结构、反应机制和结构演化的变化，这些变化是由各种晶体类型和氧化还原中心、阴离子和阳离子掺杂/取代引起的。作为聚阴离子型材料中过渡金属离子的迁移。在这篇综述中，我们重点关注钠离子电池聚阴离子型正极材料中涉及的先进表征技术，主要包括结​​构相关、形貌相关、成分相关技术以及充电/过程中的原位/操作技术。放电过程。各自的检测机制，详细讨论了每种技术的应用范围、可用信息和局限性，并总结了用于聚阴离子型材料的这些表征技术的最新进展。先进的表征技术对于理解电极材料的反应机理起着至关重要的作用，可以为设计高性能聚阴离子型正极材料和进一步优化钠离子电池的电池系统提供重要的指导原则。