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Strategies in Structure and Electrolyte Design for High‐Performance Lithium Metal Batteries

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Advanced Functional Materials
Authors:
Kaiqiang Qin at Pennsylvania State University
Kaiqiang Qin
Kathryn Holguin at George Mason University
Kathryn Holguin
Motahareh Mohammadiroudbari
Motahareh Mohammadiroudbari
Motahareh Mohammadiroudbari
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Jinghao Huang
Jinghao Huang
Jinghao Huang
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Abstract and Figures

Lithium metal is the “holy grail” anode for next‐generation high‐energy rechargeable batteries due to its high capacity and lowest redox potential among all reported anodes. However, the practical application of lithium metal batteries (LMBs) is hindered by safety concerns arising from uncontrollable Li dendrite growth and infinite volume change during the lithium plating and stripping process. The formation of stable solid electrolyte interphase (SEI) and the construction of robust 3D porous current collectors are effective approaches to overcoming the challenges of Li metal anode and promoting the practical application of LMBs. In this review, four strategies in structure and electrolyte design for high‐performance Li metal anode, including surface coating, porous current collector, liquid electrolyte, and solid‐state electrolyte are summarized. The challenges, opportunities, perspectives on future directions, and outlook for practical applications of Li metal anode, are also discussed.
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2009694 (1 of 36)
challenge, a breakthrough in high-energy
cathode and anode materials for advanced
battery technology is anticipated to further
boost the energy density of rechargeable
batteries. Among emerging battery tech-
nologies, rechargeable batteries beyond
LIBs such as Li/nickel-rich transition
metal oxide, Li–sulfur, and Li–O batteries
can deliver high energy densities of ,
, and Wh kg−, respectively, repre-
senting promising next-generation high-
energy rechargeable batteries.[–] In all
these high-energy-density battery systems,
lithium metal is used as an anode. Com-
pared to the other anode materials in LIBs
(graphite, lithium titanium oxide (LTO),
Si, Sn, and Ge), Li metal anode shows a
high theoretical capacity of mAh g−,
the lowest redox potential of −. V
versus the standard hydrogen electrode (SHE), high electronic/
ionic conductivity, and comparable cost per energy to other
anodes, demonstrating great promise for high-energy recharge-
able batteries (Figure1). More importantly, lithium metal is
the only anode that can couple with high-energy sulfur- and
O-based cathode because of the presence of lithium source in
lithium metal anode. All these merits render Li metal batteries
(LMBs) promising high-energy-density energy storage devices.
The research on LMBs can be backdated to the s, when
the first rechargeable lithium-based battery was invented by
Whittingham et al. at ExxonMobil. The first-generation LMBs,
consisting of a lithium-aluminum anode and a TiS cathode,
exhibited high energy density and a fast charging rate.[,]
However, the battery system based on a lithium metal anode
cannot last long because lithium dendrite growth upon cycling
can trigger battery thermal runaway.[,] The uncontrollable
growth of lithium dendrites and infinite relative volume change
are major challenges for the practical application of Li metal
anode.[] Due to the high reactivity of Li metal, the battery
electrolyte spontaneously forms a solid electrolyte interphase
(SEI) layer on its surface, physically blocking the direct contact
between electrolyte and lithium metal.[,] The SEI layer can
protect the lithium metal and prevent the continuous decom-
position of the electrolyte. However, the infinite volume change
and incessant growth of lithium dendrites are detrimental to
the SEI layer and trigger the formation of cracks in SEI. Due
to the tip-eect, Li dendrites tend to grow through the cracks,
further damaging the integrity of the SEI layer.[–] In addition
to damage of the SEI layer, the uneven plating and stripping of
Li dendrites during long-term cycling peels o the dendrites
Review
Strategies in Structure and Electrolyte Design for
High-Performance Lithium Metal Batteries
Kaiqiang Qin, Kathryn Holguin, Motahareh Mohammadiroudbari, Jinghao Huang,
Eric Young Sam Kim, Rosemary Hall, and Chao Luo*
Lithium metal is the “holy grail” anode for next-generation high-energy
rechargeable batteries due to its high capacity and lowest redox potential
among all reported anodes. However, the practical application of lithium
metal batteries (LMBs) is hindered by safety concerns arising from
uncontrollable Li dendrite growth and infinite volume change during
the lithium plating and stripping process. The formation of stable solid
electrolyte interphase (SEI) and the construction of robust 3D porous current
collectors are eective approaches to overcoming the challenges of Li metal
anode and promoting the practical application of LMBs. In this review, four
strategies in structure and electrolyte design for high-performance Li metal
anode, including surface coating, porous current collector, liquid electrolyte,
and solid-state electrolyte are summarized. The challenges, opportunities,
perspectives on future directions, and outlook for practical applications of
Limetal anode, are also discussed.
DOI: 10.1002/adfm.202009694
Dr. K. Qin, K. Holguin, M. Mohammadiroudbari, J. Huang, E. Y. S. Kim,
R. Hall, Prof. C. Luo
Department of Chemistry and Biochemistry
George Mason University
Fairfax, VA , USA
E-mail: cluo@gmu.edu
Prof. C. Luo
Quantum Science & Engineering Center
George Mason University
Fairfax, VA , USA
The ORCID identification number(s) for the author(s) of this article
can be found under https://doi.org/./adfm..
1. Introduction
The rapid growth of the rechargeable battery industry in the
last three decades has played an essential role in the prosperity
of modern technologies from portable electronics to electric
vehicles and renewable energies.[–] To date, the substantial
demand from the ever-growing electric vehicle market further
stimulates the development of rechargeable batteries toward the
direction of high-energy-density and high-power-density energy
storage devices. Among all types of commercial rechargeable
batteries, lithium-ion batteries (LIBs) are the “superstars” for
electric vehicles due to their high energy density and long cycle
life. However, state-of-the-art LIBs can only reach a specific
energy density of ≈ Wh kg−, which becomes a bottleneck
for LIBs consisting of a graphite-based anode and a cobalt-rich
transition metal oxide-based cathode.[,] To circumvent this
Adv. Funct. Mater. 2021, 31, 
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