In-situ constructing pearl necklace-shaped heterostructure: Zn2+ substituted Na3V2(PO4)3 attached on carbon nano fibers with high performance for half and full Na ion cells

•A strategy to optimize morphological features and crystal construction of NVP is proposed.•Pearl necklace-shaped heterostructure is constructed by electrospinning method.•CNFs bridge with each other to build a high conductive network.•Zn2+-doping generates p-type doping to introduce hole carriers and reduces band gap.•Zn0.07-ES-800 releases superior sodium storage property in half and full cells.