(ECS John B. Goodenough Award) Following the Heritage of J.B. Goodenough - the Challenge of High Energy, Safe Durable Rechargeable Batteries: From Basic Science to Practical Devices

The development of high energy density, long running rechargeable Li ion batteries, that power successfully all mobile electronic devices, can be considered as the greatest success of modern electrochemistry. This lecture reflects a journey of more than 40 years inspired by the heritage of J.B. Goodenough, a great scientist, teacher, mentor and person, one of the major contributors that enabled this success, through pioneering, systematic, highly prolific, long-term research efforts. The success in developing commercial reliable, durable and safe rechargeable Li and Li ion batteries resulted from extensive basic scientific work that has developed the capability of exploring the most complex electrodes, electrolyte solutions and reactive interfaces of these batteries by sophisticate electroanalytical tools in conjunction with advanced spectroscopic and microscopic techniques. Professor J. B. Goodenough opened new routes in materials science and solid-state electrochemistry, emphasizing multidisciplinary studies, through which it was possible to develop the most important electrodes’ materials for rechargeable Lithium batteries. The success of Li ion battery technology to conquer the power sources markets, especially for mobile electronic devices, promotes the new area of electromobility, which is a major challenge today in the field of electrochemical power sources. However, we encounter too many unsupported promises! Examples: Many publications on ‘novel’ nanomaterials, not suitable for practical battery applications, a lot of words on “beyond Li-ion batteries”, beyond for what purposes? Hard to see what can be better for electrochemical propulsion beyond Li-ion batteries, except H2/O2 fuel cells. However, it is important to mention the next huge challenge – large energy storage (hundreds of TWh globally) for enabling to mitigate the climate crisis using renewable energy resources (solar, wind). Here, modern electrochemistry is leading to a next great success in developing Na ion batteries technology (based on the most abundant elements),an impressive follow-up of Li ion batteries technology (beyond the scope of this talk). There are two main themes of this presentation: To provide vital examples how fundamental work in electroanalytical chemistry promotes development of reliable secondary batteries, emphasizing the use of in-situ analytical tools1; To examine what is the true horizons for advanced high energy density batteries that can promote further the electromobility revolution. Regarding the first theme, we pioneered the application of in-situ FTIR and Raman spectroscopies, AFM, STM, QCM, EQCM-D (the latter technique reflecting gravimetric and viscoelastic behavior of complex electrochemical systems)2 for the study of highly reactive Li and Mg electrodes in the electrolyte systems relevant to secondary Li and Mg batteries. With these methodologies we deciphered complex side reactions and passivation mechanisms of all kinds of electrodes relevant to the electrochemical energy storage & conversion field. We demonstrated comprehensive studies of a wide variety of Li, Na and Mg intercalation cathodes by a complementary use of fine electroanalytical tools – slow scanning rate CV, PITT, GITT and EIS, in conjunction with spectroscopic, microscopic and diffractometric measurements, through which we could understand ions insertion mechanisms.3 Regarding the second them, the limiting factor in Li-ion batteries in terms of energy density, cost, potential, durability and cycling efficiency are the cathode materials used. We examined most energetic cathode materials and novel approaches developed for their stabilization. We describe in this lecture promising electrode materials and methodologies of their stabilization by doping, coating, and affecting electrodes surface chemistry using active additives. Most important cathode materials for high energy density batteries comprise the 5 elements Li,Ni,Co,Mn,O at different stoichiometries that determine voltage and specific capacity. We explain how the stoichiometry dictates basic cathodes properties.4,5 We discuss the renaissance of Li metal-based rechargeable batteries. We have learned how the stabilize Li metal anodes in rechargeable batteries using reactive electrolyte solutions that induce excellent passivation through controlled surface reactions.6 We emphasize fluorinated co-solvents that open the door for a very rich surface chemistry which forms passivating surface films that behave as ideal solid electrolyte interphase (SEI) on both anodes and cathodes in advanced secondary Li batteries. This field provides indeed fascinating examples how systematic basic scientific work leads to development of most practical devices for energy storage & conversion. R e f e r ence s 1.Amalraj, S. F. et Al., Journal of Solid State Electrochem. 2011, 15, 877. 2.Aurbach, D. et Al., Account of Chemical Research, 2018, 51, 69 3.Levi, M. D. et Al., Electrochimica Acta, 1999, 45, 167. 4.Maiti, S. et Al., ACS Energy Letters, 2022, 7 ,1383 5.Aurbach, D. et Al, Energy Storage materials, 2023, 56, 25 6.Markevich, E. et Al, Journal of the American Chemical Society, 2021, 143, 21161.