Conductive 3D SW-/MW-CNTs hybrid frameworks for ultra-high-content Prussian white cathodes in sodium-ion batteries

Abstract

The need for enhancing the cyclability of Prussian white (PW) cathodes is highly desirable due to their potential as promising cathode materials for sodium-ion batteries (SIBs). In this study, an ultra-high PW content of up to 98 wt% was accomplished in PW-based cathodes via self-organization of a homogeneous 3D carbon nanotubes (CNTs) network structure. The half-cell fabricated using the PW/CNT cathode exhibited a high C-rate capability of 103.8 mAh g⁻¹ at 10C and an excellent cycling stability of 99.3% after 50 cycles at 0.2C, eliminating the need for a polymeric binder. Moreover, hybridizing multi-walled CNTs with a small amount of single-walled CNTs in a specific composition enabled the fabrication of hybrid cathode materials with sufficient electron conductivity, Na⁺ accessibility, and structural stability, making them suitable for energy storage applications. The proposed architecture of PW materials can effectively suppress irreversible phase transitions at high operating voltages by stabilizing the lattice structure and hindering the formation of undesirable phases, thus improving battery performance. Furthermore, the design of the cathode material presented in this study can effectively enhance the energy density of SIBs while maintaining high C-rate capability and cyclability.