3D Interconnected Carbon Fiber Network-Enabled Ultralong Life Na3V2(PO4)3@Carbon Paper Cathode for Sodium-Ion Batteries

Sodium-ion batteries (NIBs) are an emerging technology, which can meet increasing demands for large-scale energy storage. One of the most promising cathode material candidates for sodium-ion batteries is Na3V2(PO4)3 due to its high capacity, thermal stability, and sodium (Na) Superionic Conductor 3D (NASICON)-type framework. In this work, the authors have significantly improved electrochemical performance and cycling stability of Na3V2(PO4)3 by introducing a 3D interconnected conductive network in the form of carbon fiber derived from ordinary paper towel. The free-standing Na3V2(PO4)3-carbon paper (Na3V2(PO4)3@CP) hybrid electrodes do not require a metallic current collector, polymeric binder, or conducting additives to function as a cathode material in an NIB system. The Na3V2(PO4)3@CP cathode demonstrates extraordinary long term cycling stability for 30 000 deep charge–discharge cycles at a current density of 2.5 mA cm−2. Such outstanding cycling stability can meet the stringent requirements for renewable energy storage.