Hysteretic Phenomena between Charging and Discharging in LiNi0.5Mn1.5O4-σ. Issue 12 (1st January 2017)

• Record Type: Journal Article
• Authors: Satou, Yoshinori; Shimonishi, Yuta; Komine, Shigeki; Shimizu, Sumera; Itou, Shinich; Asai, Hideo
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 12(2017)
• Page Start: A2790
• Page End: A2793
• Publication Date: 2017-01-01
• Subjects: cathode -- lithium ion battery -- XRD; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.1551712jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Clarification of the mechanism of hysteretic phenomena between charging and discharging in LiNi0.5 Mn1.5 O4-σ under a closed-circuit voltage is crucial for achieving a high energy efficiency. We performed in situ X-ray diffraction to understand the relationship between the overpotential and the kinetically preferred state of LiNi0.5 Mn1.5 O4-σ during charging and discharging. Very different crystal structures were observed for the cathode during charging and discharging, especially in the low state-of-charge single-phase reaction region. We consider that charging can be a lithium extraction process through the large lattice spacing, and lattice shrinkage occurs just after lithium diffusion, which enables a continuous reaction. Furthermore, we consider that discharging corresponds to the continuous insertion of lithium, requiring successive "forcible" lattice expansion for the reaction to occur. A kinetic reaction model for the cathode was proposed based on these results to explain the hysteresis for charging and discharging under a closed-circuit voltage.