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Our research in energy storage spans the entire battery from the anode to the electrolyte to the cathode (see image from C&E News). The work spans a range of research from:
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Specific research includes:
- Li, Si anodes and solid electrolyte interphase research
- Metal-oxide cathodes
- Sulfur cathodes
- Electrolytes
- Development of new characterization techniques
We participate in a number of consortia, collaborations and partnerships and work with several companies near and far.
Li, Si anodes and solid electrolyte interphase research
Si Anodes - We use Si single crystals as model electrodes to study how these lithiate and how the solid electrolyte interphase layer or SEI (reaction layer that forms at electrodes) forms and evolves. The image below show the reaction scheme of the first two cycles of lithiation. See publications tab for several recent papers on this. Here is a SLAC highlight on the work. https://www-ssrl.slac.stanford.edu/content/science/highlight/2017-01-31/...
Li Anodes – Due to the intense interest in Li metal as a super high capacity anode and due to the large number of unanswered questions concerning Li metal node operation, we have recently begun several projects on Li anode cycling and the SEI layer on Li. (Image of Natalie talk coming soon)
| Electrode-Electrolyte Interface – the ordering of the electrolyte near an electrode is vitally import in diverse fields, ranging from physical chemistry, to energy storage, and heterogeneous catalysis. However, experimental determination of the structure of the electrode-electrolyte interface and electric double layer is challenging due to limited experimental approaches. We are using X-ray scattering to obtain a detailed picture of the electrode-electrolyte interface relevant to Li-ion batteries. |  |
Ge Anodes – Past research has involved Ge anodes to understand the reaction pathways and particle fracture. See publications tab for details.
Metal-oxide cathodes
Model oxide films – We use epitaxial films as model electrodes to study how these lithiate and the phase transformation pathways. These include VO2 and V2O5. Hans, Donata
Li excess
Sulfur cathodes
Video of SSRL Scientist, Johanna Nelson, Probe Lithium-Sulfur Batteries in Real Time
Electrolytes
The electrolyte used for LiS batteries have been ABC. Image of Beth's talk coming soon.
Development of new characterization techniques
We develop new characterization techniques and methodologies to understand energy storage electrodes and systems.
- X-ray based electrochemical impedance spectroscopy.
- Fast spectro- microscopy imaging.
- Cathode depth profiling.
- OPVs
Hybrid Organic-Inorganic Perovskite Solar Absorbers
Hybrid perovskites have demonstrated impressive opto-electronic properties across a wide and ever-growing compositional space, leading to the certified solar cell efficiency record of 22.1%. However, many aspects of these novel materials remain poorly understood. We focus on several aspects of these materials properties, including film formation, band gap tuning, and dynamic disorder and its importance in electron-phonon coupling.
The formation chemistry of these materials is not well-understood, even in the case of the archetypal hybrid perovskite methylammonium lead iodide (MAPbI3, MA = CH3NH3), which can be prepared from a wide variety of precursor solutions and preparation methods. We have focused on the single-step deposition of MAPbI3 from PbCl2 and 3 stoichiometric units of MAI. Films made from this PbCl2-derived method were shown in 2013 to have carrier lifetimes of hundreds of nanoseconds, and this preparation still shows some of the longest carrier lifetimes among perovskite films.
