Invited Paper SA-MoA10
Soft X-ray Spectroscopy for Fundamental Understanding and Practical Optimization of Battery Materials

Monday, November 10, 2014, 5:00 pm, Room 312

Improving the energy-density and safety of batteries remains a formidable and critical challenge for sustainable energy applications, especially for electric vehicles. The pressing demand calls for novel approaches based on modern material synthesis and advanced characterization tools. Synchrotron based soft x-ray spectroscopy is one of such incisive tools that probe the electronic states in the vicinity of the Fermi Level, which are directly related to battery operations.

This presentation will focus on the concepts of how the electronic structure revealed by soft x-ray spectroscopy could help the battery material research. The link between fundamental electron states and battery performance will first be explained in general^[1]. Several recent spectroscopic results will be discussed from both chemical and physical point of view: The chemical information delivered by soft x-ray indicates the complicated formation process of solid-electrolyte-interphases^[2]. The evolution of the transition-metal 3d states provides in-depth information of the phase transformation in positive electrodes^[3]. Key electronic states that could be directly detected by soft x-ray experiments provide clear guidelines for optimizing battery binder materials in negative electrodes^[4]. Additionally, in-situ/operando soft x-ray experiments reveal distinct charge dynamics in operating battery electrodes^[5]. Perspectives will be provided at the end on how to advance the battery material studies through novel instrumentation and methodology.

[1] Yang et al., JESRP 190, 64 (2013); [2] Qiao et al., Adv. Mater. Interf. 10.1002/admi.201300115 (2014); [3] Liu et al., JACS 134, 13708 (2012); [4] Liu et al., Adv. Mater. 23, 4679 (2011); [5] Liu et al., Nat. Commun. 4, 2568 (2013)