V. Focused Fundamental Research - EERE - U.S. Department of ...

V.C.10 Atomic Layer Deposition for Stabilization of Amorphous Silicon
Anodes (NREL, U Col)
Anne C. Dillon (Project Manager)
National Renewable Energy Laboratory
1617 Cole Blvd. Golden, CO
Phone: (303) 384-6607; Fax: (303) 384-6432
E-mail: anne.dillon@nrel.gov
Subcontractor: University of Colorado: co-P.I.’s Prof.
Steven M. George and Prof. Se-Hee Lee
Start Date: October 2010
Projected End Date: September 2014
Objectives
· Use inexpensive and scalable deposition techniques
for the production of either amorphous silicon (a-
Si) or nano-Si powders and/or doped a-Si or nano-
Si.
· Develop novel atomic layer deposition (ALD)
coatings that will enable durable cycling to be
achieved for the high volume expansion (~ 400
%)Si materials.
· Explore the importance and mechanism of various
coatings via the new BATT Coating Group.
· Collaborate within the BATT program with the aim
of developing high-rate plug-in hybrid electric
(PHEV) compatible electrodes (both anodes and
cathodes).
Technical Barriers
Major barriers addressed include:
(A) Cost: Inexpensive processing techniques are
employed to fabricate conventional thick
electrodes.
(B) High Capacity: Silicon is predominantly being
explored as a high capacity anode material. There is
also a collaborative emphasis to enable high
capacity cathode materials.
(C) High Rate: Both ALD coatings and nanostructured
materials are being developed such that high-rate
capability is demonstrated for emerging materials.
(D) Safety: The ALD coatings are targeted to improve
safety for a variety of electrode materials.
Technical Targets
· Demonstrate that ALD coatings can enable durable
cycling for high-volume expansion Si anodes with a
capacity ≥ 1000 mAh/g.
· Demonstrate ALD coatings and nanostructured or
amorphous materials for prolonged high rate
cycling.
· Demostrate that ALD coatings may serve as an
artificial solid electrolyte interphase (SEI) and will
importantly help minimize degradation upon
volume expansion.
· Explore ALD coatings to minimize the first cycle
capacity loss in Si anode materials.
Accomplishments
· This is a new award and NREL/CU have met all of
the year one milestones as outlined briefly below:
o Demonstrate scale-up of hot wire chemical
vapor deposition (HWCVD) a-Si or nano-Si
powder.
o Optimize HWCVD produced a-Si or nano-Si
in conventional coin cell.
o Demonstrate an ALD coating for improved
performance of Si anodes.
o Optimize coated electrode and demonstrate
durable cycling.
· A new Coatings Group to better understand the
importance of coatings in next-generation material
has been formed.
o Explored internally a variety of systems
including full cells to achieve better coating
understanding.
o Established collaborations with external BATT
partners including, Stan Whittingham, Clare
Grey, Arugumum Mantharam and Gao Lui to
better understand coatings via the Coatings
Group.
· Assisted in employing NREL techniqes to enable
high capacity cathodes via collaboration within
BATT.
o NREL established collaboration with Marca
Deoff for spray deposition of spinel structures.
FY 2011 Annual Progress Report 571 Energy Storage R&D