Energy Storage

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:

  • Foundational science on model electrodes aimed at detailed understanding of how batteries operate but under simplified situations
  • Operational half cells, where we use commercial anode or cathodes to investigate battery operation, capacity loss and failure
  • 3D imaging of commercial cells.
anode and cathodes  

commercial cells

Specific research includes:

We participate in a number of consortia, collaborations and partnerships and work with several companies near and far.

companies


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/...

Cycles of lithiation

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. Electrode electrolyte interface

Ge Anodes – Past research has involved Ge anodes to understand the reaction pathways and particle fracture. See publications tab for details.

GE Anodes


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

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.