Electrochemical studies in Li-O2 batteries: soluble catalysts for the enhancement of battery rechargeability

MARIA DEL POZO VAZQUEZ; R. TORRES W.R.; HERRERA S.; TESIO A.Y.; CALVO EJ,

Santander

Congreso; Second Metal Air Batteries Internationa Congress (Mabic16); 2016

Albufera Energy Storage

Electrochemical studies in Li-O2 batteries: soluble catalysts for the enhancement of battery rechargeability.Abstract:The rechargeable Li?air battery exhibits a very large theoretical energy density that can compete theoretically with fossil fuels for electric vehicle applications with an extended mileage range. The non-aqueous Li?air battery introduced in 1996 by Abraham1 consists of a lithium metal anode that dissolves in a non aqueous electrolyte and the resulting Li+ ions react with oxygen reduction products to form insoluble lithium peroxide Li2O2 at a porous carbon cathode during discharge. However there are several drawbacks in the battery performance related to discharge-charge capacity fading such as the Li2O2 oxidation kinetics, stability of carbon, solvents and lithium salts in the presence of ORR reduction products such as LiO2 and Li2O2, etc..2-3 Our work has focused on the study of the electrochemical response of the oxygen reduction reaction (ORR) in lithium containing electrolyte using different techniques, namely Electrochemical Quartz Crystal Microbalance (EQCM), Atomic Force Microscopy (AFM), Differential Electrochemical Mass Spectrometry (DEMS) and Rotating Ring Disc Electrode (RRDE). These studies aim at elucidating the determining factors of the high overpotential during the recharge cycle, solvent and electrolyte decomposition and battery capacity fading. We have studied two different soluble redox catalysts, i.e. tetratiafulvalene (TTF) and iron phtalocyanine (FePc) for the chemical re-oxidation of cathodic discharge products during ORR. In addition, FePc is also a bifunctional catalyst since it enhances the ORR by shuttling O2 coordinated as axial ligand and recycling electrons at the cathode due to the Fe(III)/Fe(II) and Fe(II)/Fe(I) redox couples in the same molecule.Key words: Lithium-oxygen battery, EQCM, redox mediator, ORRReferences:1. Abraham, K M. Jiang, Z. (1996) A Polymer Electrolyte-Based Rechargeable lithium/Oxygen Battery. Journal of Electrochemical Society, 143 (1), 1-5.2. Sharon, Daniel. Hirshberg, Daniel. Afri, Michal. Garsuch, Arnd. Frimer,Aryeh A. Aurbach, Doron. (2015) LithiumOxygen Electrochemistry in Non-Aqueous Solutions. Israel Journal of Chemistry, 55,1-14.3. McCloskey, Bryan D. Burkea, Colin M. Nicholsa, Jessica E. Renfrewa, Sara. E (2015) Mechanistic conductivity insight for limitations the development and electrolyte of Li‐O2 battery and cathode materials: addressing instabilities. (2015) Chemistry Communication, 51, 12701-12715. 4. W.R. Torres, S.E. Herrera, A.Y.Tesio, M.del Pozo, E.J. Calvo, Soluble TTF catalyst for the oxidation of cathode products in Li-Oxygen battery: A chemical scavenger. (2015) Electrochimica Acta, 182, 1118?1123.