Enhanced electrochemical performance of Ti substituted P2-Na2/3Ni1/4Mn3/4O2 cathode material for sodium ion batteries. (10th July 2015)

• Record Type: Journal Article
• Authors: Zhao, Wenwen; Tanaka, Akinobu; Momosaki, Kyoko; Yamamoto, Shinji; Zhang, Fabi; Guo, Qixin; Noguchi, Hideyuki
• Is Part Of: Electrochimica acta. Volume 170(2015)
• Page Start: 171
• Page End: 181
• Publication Date: 2015-07-10
• Subjects: Sodium ion battery -- Cathode material -- P2-Na2/3Ni1/4Mn3/4O2 -- Ti substitution -- improved electrochemical performance; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.04.125
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Ti substituted P2-Na2/3 Ni1/4 Mn3/4 O2 cathode was synthesized. Structural and electrochemical properties of Na2/3 Ni1/4 Tix Mn3/4-x O2 were studied. Ti substituted cathodes exhibit enhanced cycleability and rate performance. Ti substitution has impact on stabilizing the P2 structure during cycling. Abstract: Ti substituted P2-Na2/3 Ni1/4 Mn3/4 O2 cathode material with the composition of Na2/3 Ni1/4 Tix Mn3/4-x O2 has been synthesized by solid state method. The influence of Ti substitution for Mn on the structure, morphology and electrochemical performances of P2-Na2/3 Ni1/4 Mn3/4 O2 has been investigated. X-ray diffraction (XRD) results of Ti substituted sample show that they exhibit same diffraction patterns as those of pristine P2-Na2/3 Ni1/4 Mn3/4 O2 . Progressive change in the lattice parameters of Ti substituted samples suggests that Mn was successfully substituted by Ti. In contrast to P2-Na2/3 Ni1/4 Mn3/4 O2 which shows step-type voltage profiles, Ti substituted samples show sloping voltage profiles. Drastic capacity fade occurred for P2-Na2/3 Ni1/4 Mn3/4 O2 cathode, while Ti substituted cathodes still show high capacity retention over 92% after 25 cycles at the voltage range of 2.0-4.3 V. Even cycled at high upper cut-off voltage of 4.5 V, Ti=0.20 sample can deliver a reversible capacity of 140 mAhg −1 with the capacity retention over 92% after 25 cycles. Furthermore, Ti substituted cathodes exhibit enhanced rate capability over pristine P2-Na2/3 Ni1/4 Mn3/4 O2 cathode. Comparison of the Ex-situ XRD results of the cycled P2-Na2/3 Ni1/4 Mn3/4 O2 and its substituted samples provides evidence that the improved electrochemical performance of Ti substituted cathodes would be attributed to the stabilization of the structure with Ti substitution.