Sodium ion batteries (SIBs) based on quasi-solid-state electrolyte are a new type of energy device that exhibit high energy and security. However, the large-volume expansion and sluggish kinetics of the anode materials during the ion insertion/extraction remains a particular challenge for solid-state SIBs. In this work, flexible binder-free films composed of ultrafine VSe₂ particles wrapped in N-doped carbon nanofibers (VSe₂/NCNFs) are prepared as the anode of a quasi-solid-state SIBs. The ultra-small VSe₂ nanoparticles allow for rapid Na ion migration, and the highly graphitized carbon fibers provides a fast electronic transmission channel and stable host to relive the volume expansion of VSe₂ during cycles. Foremost, the elastic coordination between VSe₂/NCNFs and gel electrolyte can further buffer the overall volume expansion of VSe₂/NCNFs. Moreover, the flexible freestanding VSe₂/NCNFs anode combine with gel polymer in the sodium ion half-cells deliver a high reversible capacity of 420.8 mA h g⁻¹ at a current density of 0.05 A g⁻¹, excellent rate capability of 278.1 mA h g⁻¹ at 5 A g⁻¹, and 206.8 mA h g⁻¹ at 5 A g⁻¹ after 10,000 cycles. The sodium storage mechanism of VSe₂/NCNFs electrodes during the charge/discharge process is also explored by ex situ XRD in the first time.

基于准固态电解质的钠离子电池（SIB）是一种新型能量设备，具有很高的能量和安全性。然而，在离子插入/萃取过程中，阳极材料的大体积膨胀和缓慢动力学仍然是固态SIB的一个特殊挑战。在这项工作中，制备了由包裹在N掺杂的碳纳米纤维（VSe ₂ / NCNFs）中的超细VSe ₂颗粒组成的柔性无粘合剂薄膜，作为准固态SIB的阳极。超小的VSe ₂纳米颗粒可实现快速的Na离子迁移，而高度石墨化的碳纤维提供了快速的电子传输通道和稳定的主体，可重现VSe ₂的体积膨胀在周期中。最重要的是，VSe ₂ / NCNFs与凝胶电解质之间的弹性配位可以进一步缓冲VSe ₂ / NCNFs的整体体积膨胀。此外，在钠离子半电池中，柔性自立式VSe ₂ / NCNFs阳极与凝胶聚合物相结合，在0.05 A g ^-1的电流密度下可提供420.8 mA h g ^-1的高可逆容量，出色的倍率能力为278.1 mA h g ^-1在5 A G ^-1，和206.8毫安ħ克^-1在5 A G ^-1 10,000次循环后。VSe ₂的钠存储机制首次通过异位XRD探索在充放电过程中的/ NCNFs电极。