Triisopropyl borate as an electrolyte additive for improving the high voltage stability of LiNi0.6Co0.2Mn0.2O2 cathode

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 854; p. 113506
• Main Authors: Qin, Zhaoming, Hong, Shu, Hong, Bo, Duan, Boyu, Lai, Yanqing, Feng, Jiang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-12-2019; Elsevier Science Ltd
• Subjects: Cathodes; Cathodic protection; Electrolyte additive; Electrolytes; Electrolytic cells; High-voltage lithium-ion batteries; LiNi0.6Co0.2Mn0.2O2 cathode; Solid cathode electrolyte interphase; Triisopropyl borate; Voltage stability; X ray photoelectron spectroscopy; Triisopropyl borate; Electrolyte additive; Solid cathode electrolyte interphase; High-voltage lithium-ion batteries; LiNi0.6Co0.2Mn0.2O2 cathode
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2019.113506

Triisopropyl borate electrolyte additive is introduced to improve the cycled stability of LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode operating under 4.5 V charging-cutoff voltage. Through characterizations analysis from SEM, TEM, XPS, ICP, XRD and EIS, it reveals that triisopropyl borate additive can be oxidized on the cathode and form a relatively stable protective film on the NCM622 cathode surface, which has the ability to inhibit the decomposition of carbonate electrolyte solvents and improve the electrochemical stability of LiNi0.6Co0.2Mn0.2O2 cathode. When 1.0 wt% triisopropyl borate additive adding, the NCM622/Li cells achieve the discharge capacity retention of 82.7% after 300 cycles at the voltage of 3.0–4.5 V, while that of the cells without additive is only 50.0%.
•Triisopropyl borate is used as high voltage electrolyte additive for 4.5V NCM622.•Triisopropyl borate can take part in the film-forming reaction on the cathode.•The cathode electrolyte interface (CEI) can suppress the dissolution of transition metal ion from cathode.