Anode material for safe batteries with a long cycle life
Lithium lanthanum titanate particles enable high power densities even in micrometer sizes

Date:
August 6, 2020
Source:
Karlsruher Institut fu"r Technologie (KIT)
Summary:
Researchers investigated a highly promising anode material for
future high-performance batteries - lithium lanthanum titanate with
a perovskite crystal structure (LLTO). Researchers can improve the
energy density, power density, charging rate, safety, and cycle
life of batteries without requiring a decrease of the particle
size from micro to nano scale.



FULL STORY ========================================================================== Researchers at Karlsruhe Institute of Technology (KIT) and Jilin
University in Changchun/China investigated a highly promising anode
material for future high- performance batteries -- lithium lanthanum
titanate with a perovskite crystal structure (LLTO). As the team reported
in the Nature Communications journal, LLTO can improve the energy density, power density, charging rate, safety, and cycle life of batteries without requiring a decrease of the particle size from micro to nano scale.


==========================================================================
The demand for electric vehicles is increasing, accompanied by
a growing need for smart grids that ensure a sustainable energy
supply. These and other mobile and stationary technologies require
suitable batteries. Storing as much energy as possible in the smallest
possible space with the lowest possible weight - - lithium-ion
batteries (LIB) still meet this requirement best. The research aims at improving the energy density, power density, safety, and cycle life
of these batteries. The electrode material is of major importance
here. Anodes of lithium-ion batteries consist of a current collector
and an active material applied to it that stores energy in the form
of chemical bonds. In most cases, graphite is used as the active
material. However, negative electrodes made of graphite have a low
charging rate. Moreover, they are associated with safety issues. Among
the alternative active materials, lithium titanate oxide (LTO) has
already been commercialized. Negative electrodes with LTO present a
higher charging rate and are considered to be safer than those made
of graphite. The drawback is that lithium-ion batteries with lithium
titanate oxide tend to have a lower energy density.

The demand for electric vehicles is increasing, accompanied by
a growing need for smart grids that ensure a sustainable energy
supply. These and other mobile and stationary technologies require
suitable batteries. Storing as much energy as possible in the smallest
possible space with the lowest possible weight - - lithium-ion
batteries (LIB) still meet this requirement best. The research aims at improving the energy density, power density, safety, and cycle life
of these batteries. The electrode material is of major importance
here. Anodes of lithium-ion batteries consist of a current collector
and an active material applied to it that stores energy in the form
of chemical bonds. In most cases, graphite is used as the active
material. However, negative electrodes made of graphite have a low
charging rate. Moreover, they are associated with safety issues. Among
the alternative active materials, lithium titanate oxide (LTO) has
already been commercialized. Negative electrodes with LTO present a
higher charging rate and are considered to be safer than those made
of graphite. The drawback is that lithium-ion batteries with lithium
titanate oxide tend to have a lower energy density.

The team around Professor Helmut Ehrenberg, head of the Institute
for Applied Materials -- Energy Storage Systems (IAM-ESS) of KIT, now investigated another highly promising anode material: lithium lanthanum titanate with a perovskite crystal structure (LLTO). According to the
study, which was carried out in collaboration with scientists from Jilin University in Changchun (China) and other research institutes in China
and Singapore, LLTO anodes have a lower electrode potential compared
to commercialized LTO anodes, which allows for a higher cell voltage
and a higher capacity. "Cell voltage and storage capacity ultimately
determine the energy density of a battery," explains Ehrenberg. "In
the future, LLTO anodes might be used to build particularly safe high- performance cells with a long cycle life." The study contributes to
the work of the research platform for electrochemical storage, CELEST
(Center for Electrochemical Energy Storage Ulm & Karlsruhe), one of the
largest battery research platforms worldwide, which also includes the
POLiS excellence cluster.

Besides energy density, power density, safety and cycle life, the charging
rate is another determining factor for the suitability of a battery
for demanding applications. In principle, the maximum discharge current
and the minimum charging time depend on the ion and electron transport
both within the solid body and at the interfaces between the electrode
and electrolyte materials. To improve the charging rate, it is common
practice to reduce the particle size of the electrode material from micro
to nano scale. The study, which was published in the Nature Communications journal by KIT researchers and their cooperation partners, shows that
even particles of a few micrometers in size in LLTOs with a perovskite structure feature a higher power density and a better charging rate than
LTO nanoparticles. The research team attributes this to the so-called pseudocapacitance of LLTO: Not only are individual electrons attached
to this anode material, but also charged ions, which are bound by weak
forces and can reversibly transfer charges to the anode. "Thanks to the
larger particles, LLTO basically enables simpler and more cost-effective electrode manufacturing processes," explains Ehrenberg.


========================================================================== Story Source: Materials provided by
Karlsruher_Institut_fu"r_Technologie_(KIT). Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Lu Zhang, Xiaohua Zhang, Guiying Tian, Qinghua Zhang, Michael Knapp,
Helmut Ehrenberg, Gang Chen, Zexiang Shen, Guochun Yang, Lin Gu,
Fei Du.

Lithium lanthanum titanate perovskite as an anode for lithium
ion batteries. Nature Communications, 2020; 11 (1) DOI:
10.1038/s41467-020- 17233-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200806111828.htm

--- up 3 weeks, 1 day, 1 hour, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)