Electrochemical Properties of the LiNi0.6Co0.2Mn0.2O2 Cathode Material Modified by Lithium Tungstate under High Voltage

Jiale Fu; Daobin Mu; Borong Wu; Jiaying Bi; Hui Cui; Hao Yang; Hanfeng Wu; Feng Wu

doi:10.1021/acsami.8b04167

Electrochemical Properties of the LiNi_0.6Co_0.2Mn_0.2O₂ Cathode Material Modified by Lithium Tungstate under High Voltage

ACS Appl Mater Interfaces. 2018 Jun 13;10(23):19704-19711. doi: 10.1021/acsami.8b04167. Epub 2018 May 31.

Authors

Jiale Fu¹, Daobin Mu¹, Borong Wu^{1

2}, Jiaying Bi¹, Hui Cui¹, Hao Yang¹, Hanfeng Wu³, Feng Wu^{1

2}

Affiliations

¹ School of Materials Science and Engineering, Beijing Key Laboratory of Environment Science and Engineering , Beijing Institute of Technology , Beijing 100081 , China.
² Collaborative Innovation Center of Electric Vehicles in Beijing , Beijing 100081 , China.
³ School of Materials Science and Engineering , Beijing University of Technology , Beijing 100022 , China.

PMID: 29790731
DOI: 10.1021/acsami.8b04167

Abstract

An amount (5 wt %) of lithium tungstate (Li₂WO₄) as an additive significantly improves the cycle and rate performances of the LiNi_0.6Co_0.2Mn_0.2O₂ electrode at the cutoff voltage of 4.6 V. The 5 wt % Li₂WO₄-mixed LiNi_0.6Co_0.2Mn_0.2O₂ electrode delivers a reversible capacity of 199.2 mA h g^-1 and keeps 73.1% capacity for 200 cycles at 1 C. It retains 67.4% capacity after 200 cycles at 2 C and delivers a discharge capacity of 167.3 mA h g^-1 at 10 C, while those of the pristine electrode are only 44.7% and 87.5 mA h g^-1, respectively. It is shown that the structure of the LiNi_0.6Co_0.2Mn_0.2O₂ cathode material is not affected by mixing Li₂WO₄. The introduced Li₂WO₄ effectively restrains the LiPF₆ and carbonate solvent decomposition by consuming PF₅ at high cutoff voltage, forming a stable cathode/electrolyte interface film with low resistance.

Keywords: LiNi0.6Co0.2Mn0.2O2 cathode; high cut-off voltage; interface; lithium ion batteries; lithium tungstate.