Secondary Battery Science: At the Confluence of Electrochemistry and Materials Engineering.

Considerations of energy density, power, and calendar life are critical to effectively develop advanced secondary systems. For next generation battery applications requiring multiple features including long life, large cycle count, high energy density and high power, new strategies are needed for the rational design of electroactive materials and electrodes. This article discusses several conceptual approaches under exploration with examples from our research group. The first approach is the systematic synthesis of materials with structures facilitating ion insertion and deinsertion at high voltage and energy density, where we control materials properties such as surface area, particle size and in particular crystallite size. A second approach is the investigation of novel electrode structures and substrates to increase energy density and capacity retention under cycling, where we have developed strategies for minimizing passive components. A third approach is investigation of catalysts for metal air batteries where the cathode active material is drawn from the air rather than carried in the battery.