Effects of excess Li on the structure and electrochemical performance of Li1+zMnTiO4+δ cathode for Li-ion batteries. (20th January 2017)

• Record Type: Journal Article
• Authors: Vu, Ngoc Hung; Arunkumar, Paulraj; Won, Seob; Kim, Ha Jun; Unithrattil, Sanjith; Oh, Yoong; Lee, Jong-Won; Im, Won Bin
• Is Part Of: Electrochimica acta. Volume 225(2017)
• Page Start: 458
• Page End: 466
• Publication Date: 2017-01-20
• Subjects: LiMnTiO4 -- cycle stability -- spinel-layered composite -- stable spinel framework; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.12.180
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Spinel-based LiMn2 O4 is the most attractive cathode for Li-ion battery due to high voltage, low cost, and non-toxicity. The cycle life of the spinel cathodes could be improved by replacing Mn 4+ with Ti 4+ leading to the formation of new spinel cathode, LiMnTiO4 . However, its application is restricted due to the associated loss in the specific capacity. In this work, spinel-layered Li1+ z MnTiO4+ δ ( z = 0, 0.5, and 1.0; δ is the value to reflect the composite character of the material) cathodes were fabricated to achieve long cycle life, without compromising on the specific capacity. Cathodes with excess Li ( z = 0.5 and 1.0) formed a spinel-layered composite structure with notation (1- a )LiMn2- x Ti x O4 . a Li2 Mn y Ti1- y O3 [ y = 0.5–((1/ a − 1)(1 − x ))]. These cathodes exhibited an enhanced specific capacity of ∼218 mAh g −1 (20% higher), with a capacity retention of 94% after 60 cycles. The structural and electrochemical properties of these cathodes were investigated using X-ray diffraction, galvanostatic cycling, cyclic voltammetry, and the galvanostatic intermittent titration technique to understand the mechanisms underlying the enhanced capacity and cycle stability. The effect of the Li-rich layered phase on the electrochemical performance of the Li1+ z MnTiO4+ δ cathodes was also investigated.