Cesium-Based Additive Leads to More Stable Lithium Metal Batteries

X-ray fluorescence images enlarge

Top: X-ray fluorescence images showing the distribution of Cs species on the surface of NMC811 (positive electrode) and Li metal after 200 cycles in the electrolyte containing the CsNO3 additive. Bottom: Comparison of cycling performance with and without CsNO3 additive. Credit: Nat Commun 14, 8414 (2023).

The Science         

Researchers used cesium nitrate (CsNO3) to stabilize the electrodes of lithium (Li) metal batteries.

The Impact

Cesium additives may be a key to achieving longer-lasting Li metal batteries with improved charging properties.


On a mission to build better electric vehicle batteries, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have used an additive to improve the functionality of lithium (Li) metal batteries. By adding a compound called cesium nitrate to the electrolyte that separates the battery’s negative and positive electrodes—the anode and cathode, respectively—the research team has significantly improved the charging rate of Li metal batteries while maintaining a long cycle life.

Li metal batteries are not the same as Li-ion batteries, which power many everyday electronic devices, such as smart phones and laptops, as well as electric vehicles. The two types have different chemical makeups: For example, Li ion batteries typically use graphite, a form of carbon, as the anode material, while Li metal batteries use pure Li metal as the anode.

Li metal batteries may be the next generation of lithium batteries, due to their significantly higher energy density – electric vehicles powered by these batteries could go much longer and further without needing to charge and could also recharge much faster. But much more research needs to be done before these goals can be met.

The team’s new work targets the protective layer formed on the battery’s anode and cathode, known as the interphase. This layer, which prevents degradation of battery electrodes, is the key to creating Li metal batteries that can be charged and discharged as many times as Li ion batteries. The scientists found that the cesium nitrate additive increased the presence of components known to make the interphase more protective.

They studied the additive's effect on battery performance using four beamlines at National Synchrotron Light Source II, a DOE Office of Science User Facility at Brookhaven Lab: X-ray Powder Diffraction (XPD), Submicron Resolution X-ray Spectroscopy (SRX), Quick X-ray Absorption and Scattering (QAS), and In Situ and Operando Soft X-ray Spectroscopy (IOS). They also used scanning electron microscopy at the Center for Functional Nanomaterials, another DOE Office of Science User Facility located at the Lab.

By combining various techniques across two user facilities, the scientists were able to paint a full picture of how the lithium metal battery behaves with the cesium nitrate additive. This research contributes to a better understanding of interphase optimization and overall battery chemistry.

Download the research summary slide (PDF)


Enyuan Hu
Brookhaven National Laboratory


Rahman, M.M., Tan, S., Yang, Y., Zhong H., Ghose, S., Waluyo, I., Hunt, A., Ma, L., Yang, X., Hu, E. An inorganic-rich but LiF-free interphase for fast charging and long cycle life lithium metal batteriesNat Commun 14, 8414 (2023). DOI: https://doi.org/10.1038/s41467-023-44282-z


The work at BNL is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy (EERE), Vehicle Technology Office (VTO) of the US Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) Program including the Battery500 Consortium under contract no. DE-SC0012704. This research used beamlines 5-ID, 7-BM, 23-ID-2, 28-ID-2 of the National Synchrotron Light Source II, a US DOE Office of Science user facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract number DE-SC0012704. SEM measurements used the resources of the Center for Functional Nanomaterials, a US DOE Office of Science User Facility at BNL, under contract no. DE-SC0012704. We also acknowledge the US DOE CAMP (Cell Analysis, Modeling and Prototyping) Facility, Argonne National Laboratory for supplying the NMC811 electrodes. The CAMP Facility is fully supported by the DOE Vehicle Technologies Office.

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