Pavithra Murugavel Shanthi

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.

Fluorine substituted (Mn,Ir)O2:F high performance solid solution oxygen evolution reaction electro-catalysts for PEM water electrolysis

Identification and development of high performance with reduced overpotential (i.e. reduced operating electricity cost) oxygen evolution reaction (OER) electrocatalysts for proton exchange membrane (PEM) based water electrolysis with ultra-low noble metal content (i.e. reduced materials cost) is of significant interest for economic hydrogen production, thus increasing the commercialization potential of PEM water electrolysis. Accordingly, a novel electrocatalyst should exhibit low overpotential, excellent electrochemical activity and durability superior to state of the art noble metal based electro-catalysts (e.g. Pt, IrO2, RuO2). Herein, for the very first time to the best of our knowledge, exploiting first-principles theoretical calculations of the total energies and electronic structures, we have identified a reduced noble metal content fluorine doped solid solution of MnO2 and IrO2, denoted as (Mn1−xIrx)O2:F (x = 0.2, 0.3, 0.4), OER electrocatalyst system exhibiting lower overpotential and higher current density than the state of the art IrO2 and other previously reported systems for PEM water electrolysis. The doped solid solution displays an excellent electrochemical performance with a lowest reported onset potential to date of ∼1.35 V (vs. RHE), ∼80 mV lower than that of IrO2 (∼1.43 V vs. RHE) and ∼15 fold (x = 0.3 and 0.4) higher electrochemical activity compared to pure IrO2. In addition, the system displays excellent long term electrochemical durability, similar to that of IrO2 in harsh acidic OER operating conditions. Our study therefore demonstrates remarkable, ∼60–80% reduction in noble metal content along with lower overpotential and excellent electrochemical performance clearly demonstrating the potential of the (Mn1−xIrx)O2:F system as an OER electro-catalyst for PEM water electrolysis.

A New Lamination and doping Concepts for Enhanced Li – S Battery Performance

• Objective: The project aims to develop commercially viable lithium battery technologies with a cell level specific energy of 500 Wh/kg through innovative electrode and cell designs that enable the extraction of the maximum capacity from advanced electrode materials. In addition, the project aims to achieve 1000 cycles for the developed technologies Impact: • The results of this project will be used for the development of technologies that will significant increase the energy density, cycle life and reduce the cost of rechargeable batteries for electric vehicles Title of Graph: Battery500 team developed Cryo TEM to study the Li metal anode for high energy density batteries PI/Co-PI Jun Liu (PNNL) and Yi Cui (Stanford University)