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Effect of solvent composition on the electrochemical performance of high-voltage cathode LiNi0.5Mn1.5O4

The spinel LiNi0.5Mn1.5O4 (LNMO) is considered as an accurate cathode material for highvoltage Li-ions batteries above 4.5 V due to its high energy density, safety and eco-friendly. The electrochemical performance of spinel LNMO depends on the combability between electrode material and electrolyte. | Vietnam Journal of Science and Technology 56 (2A) (2018) 69-74 EFFECT OF SOLVENT COMPOSITION ON THE ELECTROCHEMICAL PERFORMANCE OF HIGH-VOLTAGE CATHODE LiNi0.5Mn1.5O4 Huynh Thi Kim Tuyen1, Huynh Le Thanh Nguyen1, Nguyen Ngoc Minh1,2, Le My Loan Phung1,2, Tran Van Man1,2,* 1 Applied Physical Chemistry Laboratory (APCLAB), VNUHCM-University of Science, 227 Nguyen Van Cu St., District 5, Ho Chi Minh City 2 Department of Physical Chemistry, Faculty of Chemistry, VNUHCM-University of Science, 227 Nguyen Van Cu St., District 5, Ho Chi Minh City * Email: tvman@hcmus.edu.vn Received: 26 April 2018; Accepted for publication: 12 May 2018 ABSTRACT The spinel LiNi0.5Mn1.5O4 (LNMO) is considered as an accurate cathode material for highvoltage Li-ions batteries above 4.5 V due to its high energy density, safety and eco-friendly. The electrochemical performance of spinel LNMO depends on the combability between electrode material and electrolyte. In this work, we reported the essential role of solvent compositions– carbonate solvents such as ethylene carbonate (EC), dimethyl carbonate (DMC), ethylene methyl carbonate (EMC)–in 1 M LiPF6 electrolytes on the long-term cycling test. The volumetric ratios in which the solvent compositions were varied were as follows: EC-EMC (7:3), EC-EMC (1:1), EC-DMC (1:1), EC-DMC (1:2). Result of cycling test in the solvent EC-EMC (7:3) leads to a discharge capacity of 140 mAh/g and a retention of 85 % initial capacity after 50 cycles. Keywords: cycling test, dimethyl carbonate (DMC), ethylene carbonate (EC), ethylene methyl carbonate (EMC), LiNi0.5Mn1.5O4. 1. INTRODUCTION Since the commercialization in 1991, Lithium-ion batteries (LIBs) have the lead in a market of rechargeable batteries because its long-life cycle, high energy density and power density are more outstanding than other secondary batteries. The commercial LIBs utilize lithiated carbon as anode and LiCoO2 as cathode, which provide a voltage operation of 3.4 V and energy density .