CTAB-assisted multiwalled carbon nanotube-loaded NaFe2Mn(PO4)3 materials as high performance cathodes for sodium-ion batteries

Abstract

The development of a NaFe₂Mn(PO₄)₃ cathode material has been limited by the intrinsically low electrical conductivity. In this work, in order to overcome the issues, the multiwalled carbon nanotube (MWCNTs) loaded NaFe₂Mn(PO₄)₃ nanosheets with CTAB (cetyltrimethylammonium bromide) are synthesized via a simple solvothermal method. The addition of CTAB is conducive to improve the dispersion of the MWCNTs and decrease the size of nanosheets. Moreover, the electrochemical performance of the NaFe₂Mn(PO₄)₃/MWCNTs material with 3% MWCNTs is the best. At a current density of 20 mA g⁻¹, the discharge capacity of NaFe₂Mn(PO₄)₃/MWCNTs materials is 164.5 mA h g⁻¹ in the first cycle, and the discharge capacity is 120.2 mA h g⁻¹ after 50 cycles. The excellent electrode performance is ascribed to the contribution of the nanosheets morphology and 3D carbon framework, which can favor the migration of electrons and ions. The electrochemical performance of NaFe₂Mn(PO₄)₃ materials have been improved by adding the MWCNTs and CTAB.