Co0.85Se@carbon nanotubes surface-seeding grown on carbon microplates as superior anode material for sodium ion batteries

•The Co0.85Se@CNT-CP composites were elaborately fabricated by a simple pyrolysis-selenization strategy.•The fluffy 3D structure not only provides efficient pathways for quick electrons and Na+ entrance, but also helps to reduce the volume-change effect during the charge@discharge cycles. Furthermore, the composites displayed a superior Na+ storage performance.•In-depth electrochemical kinetic investigations revealed the pseudocapacitive behavior of the composites for storge of Na+.