Tailoring the surface chemistry to enhance corrosion resistance lies at the heart of materials processing for corrosion control of structural materials. This conventional wisdom, however, can fail miserably when the underlying materials’ function(s) involves chemical reactions. In this talk, I will introduce the concepts of surface passivation and passivity breakdown. I will show that, by tuning the surface composition, passivation can lead to successful optimization of intercalation cathode materials in lithium ion batteries (LIBs).^[1,2] On the other hand, self-passivation in anode materials can significantly alter the rate performance of LIBs.^[3,4] I will show that the rate capacity of a large family of phase conversion anode materials, i.e. transition metal oxides, is dependent on the stochastic process of passivity breakdown which can be described by a Poisson model.^[5] This model can answer the long standing question—why transition metal oxides conversion materials perform much more poorly in sodium ion batteries than in LIBs, even though sodium ions can diffuse equally fast as lithium does in these materials.^[6]

Reference

^[1] Metal segregation in hierarchically structured cathode materials for high-energy lithium batteries, Feng Lin, et al, Yijin Liu*, H L Xin*, M Doeff*, Nature Energy, 1, 15004 (2016)

^[2] Surface reconstruction and chemical evolution of stoichiometric layered cathode materials for lithium-ion batteries, Feng Lin, Isaac Markus, Dennis Nordlund, Tsu-Chien Weng, Mark Asta, H. L. Xin*, M. M. Doeff, Nature Communications, 5, 3529

^[3] Phase Evolution for Conversion Reaction Electrodes in Lithium-ion Batteries, Feng Lin, Dennis Nordlund, Tsu-Chien Weng, Ye Zhu, Chunmei Ban, Ryan Richards, and H L Xin*, Nature Communications, 5, 3356

^[4] Three-dimensional hollow-structured binary oxide particles as an advanced anode material for high-rate and long cycle life lithium-ion batteries, Deli Wang, et al, H L Xin*, Nano Energy, 20, 212 (2016)

^[5] Transitions from Near-Surface to Interior Redox upon Lithiation in Conversion Electrode Materials, Kai He et al, Nano Letters, 15, 1437 (2015)

^[6] Sodiation Kinetics of Metal Oxide Conversion Electrodes: a Comparative Study with Lithiation, Kai He, et al H L Xin*, Dong Su*, Nano Letters, 15, 5755

Acknowledgement

HLX acknowledges contributions from all coauthors, to name a few, Feng Lin, Kai He, Dong Su, Marca Doeff, Yijin Liu, Eric Stach, Ryan Richards, Xiqian Yu, Xiao-Qing Yang, Dennis Nordlund, and Deli Wang. This research is supported in part by the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704, and by Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. This research made use of resources of Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515.