Utilization of biomass pectin polymer to build high efficiency electrode architectures with sturdy construction and fast charge transfer structure to boost sodium storage performance for NASICON-type cathode

Abstract

Despite recent advances in the development of suitable electrode materials for sodium-ion batteries, it remains a daunting challenge to achieve better Na⁺ storage performance without introducing new drawbacks. To improve the cycle stability and rate performance of Na₃V₂(PO₄)₃, most attention has been directed to improving the electronic conductivity by carbon compositing. However, excess carbon increases the difficulty of adhering the active materials. Besides, the ionic insulation of PVDF hinders the transfer of Na⁺, which severely limits the rate capability. Herein, we proposed a strategy of using biomass pectin polymer to build an electrode architecture with a sturdy construction and fast charge transfer structure. The rich carboxylic and hydroxyl groups endow pectin with a strong binding force that protects the integrity of the electrode and avoids exfoliation of the active materials. Thus, the sturdy construction enables Na₃V₂(PO₄)₃/C (NVP) to run for over 15 000 cycles. In addition, the construction of the conductive framework accelerates the fast transfer of the ion/electron, thereby giving rise to its enhanced rate capability. Thus NVP with even low carbon content of 1.15% could demonstrate superior rate capability at 100C rate. The rational design strategy in this study provides a new perspective for the optimizing electrode structure rather than material modification.