Analysis of redox additive-based overcharge protection for rechargeable lithium batteries

• Published in: Journal of the Electrochemical Society Vol. 138; no. 8; pp. 2224 - 2229
• Main Authors: Narayanan, S. R., Surampudi, S., Attia, A. I., Bankston, C. P.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Electrochemical Society 01.08.1991
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy Production And Conversion; Exact sciences and technology; Additive; Experimental result; Redox couple; Voltage current curve; Electrolyte; Simulation; Overload; Lithium; Secondary cell; Models; Protection; Electrochemical characteristic
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.2085954

The overcharge condition in secondary lithium batteries employing redox additives for overcharge protection, has been theoretically analyzed in terms of a finite linear diffusion model. The analysis leads to expressions relating the steady-state overcharge current density and cell voltage to the concentration, diffusion coefficient, standard reduction potential of the redox couple, and interelectrode distance. The model permits the estimation of the maximum permissible overcharge rate for any chosen set of system conditions. Digital simulation of the overcharge experiment leads to numerical representation of the potential transients, and estimate of the influence of diffusion coefficient and interelectrode distance on the transient attainment of the steady state during overcharge. The model has been experimentally verified using 1,1-prime-dimethyl ferrocene as a redox additive. The analysis of the experimental results in terms of the theory allows the calculation of the diffusion coefficient and the formal potential of the redox couple. The model and the theoretical results may be exploited in the design and optimization of overcharge protection by the redox additive approach.