(6en) Fundamental Discovery and Materials Design for Energy Storage

Yuzhang Li - Ph.D. `18
(Stanford University)

Research Interests:

Electrochemical
energy conversion and storage is critical for vehicle electrification and
storing clean energy from intermittent sources (i.e. wind, solar) on the grid. Towards
these goals, my work as a doctoral student has encompassed the broad spectrum
of stages necessary for technological innovation: (1) developing new tools to
discover fundamental understandings, (2) designing and synthesizing unique
materials to address intrinsic failure modes, and (3) patenting the technology
for real world applications.

As a doctoral
student, I have developed [1] and patented [2] a novel graphene cage materials design approach
that enables silicon (Si) to cycle as a lithium-ion battery anode with over
four times the theoretical capacity of commercial graphite (372 mAh g^-1).
Using in situ transmission electron microscopy (TEM), I showed that the graphene
cage is electrically conductive and mechanically robust enough to overcome the
dramatic failure modes (i.e. particle rupture, unstable interface) of Si during
battery operation. This work is important because it demonstrated for the first
time that fractured Si particles could still be recharged in a battery, something
that the battery community believed to be previously impossible. Furthermore,
the concept of direct graphene growth on each Si particle shows that simple
physical mixing of two materials may be insufficient to achieve the desired
properties of a composite materials system.

Looking beyond Si,
I established strategies to investigate fundamental aspects of pure lithium
(Li) metal, which can potentially enable batteries with energy density
approaching that of gasoline. Previous techniques were unable to study Li metal
at the nanoscale due to its extreme reactivity to the ambient environment and
sensitivity to the electron beam. Using environmental [3]
and cryogenic [4] TEM techniques that I
developed, my research revealed the nanoscale corrosion behavior and detailed
crystallography of Li metal dendrites. The new insights guided the design of a
protective nitride layer that enabled improved cycling stability of Li metal. My
results represent a simple but telling demonstration of the practical
applications that can be initiated by fundamental studies on reactive battery
materials. These newly developed techniques open up many excellent
opportunities for future scientific discovery and invention.

My future research
seeks to develop fundamental understandings of the working mechanisms and
failure modes in electrochemical devices at both the macroscopic and atomic
scale. Guided by these insights, I will design, synthesize, and characterize materials
systems that can overcome intrinsic challenges and enable devices for practical
application. Using the advanced characterization tools and chemistry expertise
developed in my doctoral studies, I intend to further study the atomic
structure of electrocatalysts at reaction conditions to understand their
behavior during operation [5].

Selected
Publications:

[1]: Y. Li,
K. Yan, H.W. Lee, Z. Lu, N. Liu, Y. Cui. Nature Energy 1 (2016):
15029.

[2]: Y. Li,
K. Yan, Z. Lu, Y. Cui. US Patent Application No. 15/178,366. (2016).

[3]: Y. Li,
Y. Li, Y. Sun, B. Butz, K. Yan, A.L. Koh, J. Zhao, A. Pei, Y. Cui. Nano Letters
17.8 (2017): 5171-5178.

[4]: Y. Li,
Y. Li, A. Pei, K. Yan, Y. Sun, C.L. Wu, L.M. Joubert, R. Chin, A.L. Koh, Y. Yu,
J. Perrino, S. Chu, Y. Cui. Science 358.6362 (2017): 506-510.

[5]: H. Wang, S.
Xu, C. Tsai, Y. Li, C. Liu, J. Zhao, Y. Liu, H. Yuan, F.
Abild-Pedersen, F.B. Prinz, J.K. Norskov, Y. Cui. Science 354.6315
(2016):1031-1036.

Teaching Interests:

My teaching
audiences have spanned middle school students to post-doctoral scholars. These
experiences have trained my ability to clearly explain difficult concepts in a
simple or detailed manner. Coming from a chemical engineering undergraduate
background, I am excited to teach a variety of courses at the undergraduate and
graduate levels. In particular, I am interested in teaching materials
chemistry, transport phenomena (heat, mass, momentum), and atomic structure and
arrangements. Creating a great educational experience for young scientists and
researchers is critical for the continued advancement of science and it is with
this view that I will approach teaching as a future faculty member.

Proposal
Experience:

-       Office of Energy Efficiency and Renewable
Energy Materials Research Program (2016)

-       Department of Energy Batteries for
Advanced Transportation Technologies (2016)

-       Intelligence Community Postdoctoral
Research Fellowship (2018)