TY - JOUR
T1 - Thermal characteristics of conversion-type FeOF cathode in li-ion batteries
AU - Zhao, Liwei
AU - Kitajou, Ayuko
AU - Okada, Shigeto
N1 - Funding Information:
This work was performed under the Cooperative Research Program of "Network Joint Research Center for Materials and Devices". We also received financial support from "Elements Strategy Initiative for Catalysts & Batteries (ESICB)" program of MEXT, Japan.
Publisher Copyright:
© 2017 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2017/12
Y1 - 2017/12
N2 - Rutile FeOF was used as a conversion-type cathode material for Li-ion batteries. In the present study, 0.6Li, 1.4Li, and 2.7Li per mole lithiation reactions were carried out by changing the electrochemical discharge reaction depth. The thermal characteristics of the FeOF cathode were investigated by thermogravimetric mass spectrometric (TG-MS) and differential scanning calorimeter (DSC) systems. No remarkable HF release was detected, even up to 700◦C, which indicated a low toxic risk for the FeOF cathode. Changes in the thermal properties of the FeOF cathode via different conversion reaction depths in the associated electrolyte were studied by changing the cathode/electrolyte ratio in the mixture. LiFeOF was found to exothermically react with the electrolyte at about 210◦C. Similar exothermic reactions were found with charged FeOF cathodes because of the irreversible Li ions. Among the products of the conversion reaction of FeOF, Li2 O was found to exothermically react with the electrolyte at about 120◦C, which induced the main thermal risk of the FeOF cathode. It suggests that the oxygen-containing conversion-type cathodes have a higher thermal risk than the oxygen-free ones, but controlling the cathode/electrolyte ratio in cells successfully reduced the thermal risk. Finally, the thermal stability of the FeOF cathode was evaluated in comparison with FeF3 and LiFePO4 cathodes.
AB - Rutile FeOF was used as a conversion-type cathode material for Li-ion batteries. In the present study, 0.6Li, 1.4Li, and 2.7Li per mole lithiation reactions were carried out by changing the electrochemical discharge reaction depth. The thermal characteristics of the FeOF cathode were investigated by thermogravimetric mass spectrometric (TG-MS) and differential scanning calorimeter (DSC) systems. No remarkable HF release was detected, even up to 700◦C, which indicated a low toxic risk for the FeOF cathode. Changes in the thermal properties of the FeOF cathode via different conversion reaction depths in the associated electrolyte were studied by changing the cathode/electrolyte ratio in the mixture. LiFeOF was found to exothermically react with the electrolyte at about 210◦C. Similar exothermic reactions were found with charged FeOF cathodes because of the irreversible Li ions. Among the products of the conversion reaction of FeOF, Li2 O was found to exothermically react with the electrolyte at about 120◦C, which induced the main thermal risk of the FeOF cathode. It suggests that the oxygen-containing conversion-type cathodes have a higher thermal risk than the oxygen-free ones, but controlling the cathode/electrolyte ratio in cells successfully reduced the thermal risk. Finally, the thermal stability of the FeOF cathode was evaluated in comparison with FeF3 and LiFePO4 cathodes.
UR - http://www.scopus.com/inward/record.url?scp=85065523442&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85065523442&partnerID=8YFLogxK
U2 - 10.3390/batteries3040033
DO - 10.3390/batteries3040033
M3 - Article
AN - SCOPUS:85065523442
SN - 2313-0105
VL - 3
JO - Batteries
JF - Batteries
IS - 4
M1 - 33
ER -