In situ 7Li nuclear magnetic resonance study of the relaxation effect in practical lithium ion batteries

被引：47

作者：

Gotoh, Kazuma ^{[1
]}

Izuka, Misato ^{[1
]}

Arai, Juichi ^{[2
]}

Okada, Yumika ^{[2
]}

Sugiyama, Teruyasu ^{[2
]}

Takeda, Kazuyuki ^{[3
]}

Ishida, Hiroyuki ^{[1
]}

机构：

[1] Okayama Univ, Grad Sch Nat Sci & Technol, Okayama 7008530, Japan

[2] Yamaha Motor Co Ltd, Iwata, Shizuoka 4388501, Japan

[3] Kyoto Univ, Grad Sch Sci, Div Chem, Kyoto 6068502, Japan

来源：

CARBON | 2014年 / 79卷

关键词：

HARD-CARBON; ELECTROCHEMICAL INTERCALATION; NMR; INSERTION; GRAPHITE; ELECTRODES; ANODE;

D O I：

10.1016/j.carbon.2014.07.080

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Lithium ion cells comprising actual components of positive electrodes (LiCoO2, LiNixCoyAlz, and LiMn2O4) and negative electrodes (graphite and hard carbon) were assembled for in situ Li-7 nuclear magnetic resonance (NMR) experiments. The Li-7 NMR measurements of the cells revealed a "relaxation effect" after overcharging: a decrease of the signal assigned to Li metal deposited on the negative electrode surface by overcharging. The reduction of the Li metal signal was inversely proportional to the increase of the signal of lithium stored in carbon. Therefore, the effect was ascribed to absorption of deposited lithium into the carbon of negative electrodes. The effect, which occurred rapidly in a few hours, reached an equilibrium state at 8-15 h. The slight shift of deposited metal suggests that dendritic Li easily re-dissolved, although larger Li particles remained. A hard carbon electrode has a greater effect of Li metal relaxation than graphite electrodes do, which is explainable by the bufferable structure of the carbon. Results are expected to be important for the discussion of the state of lithium, and for safer battery design. (C) 2014 Elsevier Ltd. All rights reserved.

引用

页码：380 / 387

页数：8

共 23 条

[1] In Situ Solid-State NMR Spectroscopy of Electrochemical Cells: Batteries, Supercapacitors, and Fuel Cells [J].