Effects of binders on electrochemical performance of nitrogen-doped carbon nanotube anode in sodium-ion battery

N-doped hollow carbon nanotubes (N-CNTs) with turbostratic structure are prepared as anode materials for sodium-ion battery. The effects of sodium polyacrylate (Na-PAA) and poly(vinylidene difluoride) (PVDF) binders on electrochemical performance are comparatively investigated. The obtained N-CNTs have disordered carbon structure and contain N-, O-functional groups, which electrochemical performance strongly depends on the binder used. The N-CNTs electrode with Na-PAA binder exhibits large capacity, high initial coulombic efficiency, excellent cycling stability and rate performance. Compared with the traditional PVDF binder, the water soluble Na-PAA binder shows electrochemical activity, lower internal resistance, and homogeneously formed solid electrolyte interface. Further investigations show that the binding capability of Na-PAA is closely related to the molecular weight. The Na-PAA with moderate molecular weight is more suitable as the binder of sodium-ion batteries with N-CNTs anode. (C) 2015 Elsevier Ltd. All rights reserved.