Improving electrochemical performance of Na4MnV(PO4)3 cathode material through Ti substitution

Abstract

• The synthesis of Na 3+x MnTi 1-x V x (PO 4 ) 3 is facile. • The structure evolution and electrochemical performance of Na 3+x MnTi 1-x V x (PO 4 ) 3 are revealed. • Na 3.7 MnTi 0.3 V 0.7 (PO 4 ) 3 exhibits excellent cycle stability and rate capability as cathode material for Na-ion battery. Mn-based NASICON (Na super ionic conductor)-typed compounds are potentially applied as cathode materials for Na-ion batteries. However, cycling instability and poor rate capability limits its large-scale application. Herein, Na 3+x MnTi 1-x V x (PO 4 ) 3 with various Ti/V ratios were synthesized. The influence of the Ti/V ratios on the composition, structure and electrochemical properties were investigated. With increasing with content of V, cell parameters a (and b) and cell volume increases. Among these materials, Na 3.7 MnTi 0.3 V 0.7 (PO 4 ) 3 exhibits the best cycle stability and rate capability (62.7 mAh/g at 5 C, 53.2 mAh/g at 10 C), demonstrating potential application as cathode material for Na-ion batteries.