Demonstrating the Feasibility of Highly Stable, Sodium-Ion Batteries

The Science

Sodium-ion batteries are an attractive alternative to lithium-ion batteries because of their high efficiency and low cost, but development of sodium-ion batteries with high-energy density and long cycle life has been a major challenge. A team of researchers recently overcame this hurdle by developing a high-energy sodium-ion battery that exhibits long-term cycling stability.

The Impact

By demonstrating the feasibility of high-performance sodium-ion batteries, this work could pave the way for widespread implementation of low-cost, high-efficiency energy storage devices for the electrical grid and electric vehicles.

Summary

With the growing use of electric vehicles and extensive implementation of intermittent renewable energy in electrical grids, inexpensive and highly efficient large-scale energy storage devices are needed. Lithium-ion batteries dominate energy storage technologies for portable electronics because of their superior performance in power, energy density, and cycle life. However, limited abundance of lithium makes these batteries too costly for widespread use for the grid and electric vehicles. Because of chemical similarities between sodium ions and lithium ions and abundant sodium resources in Earth’s crust, sodium-ion batteries are promising as a high-efficiency, low-cost energy storage alternative to lithium-ion batteries. Nonetheless, major drawbacks of sodium-ion batteries have been their relatively low-energy density and short cycle life. To address this problem, a team of researchers from the U.S. Department of Energy’s (DOE) Pacific Northwest National Laboratory and Environmental Molecular Sciences Laboratory (EMSL) synthesized a sodium manganese oxide as a cathode and hard carbon as an anode, and they assembled a rechargeable sodium-ion battery. The sodium-ion battery exhibited high capacity, high-energy density, and excellent long-term cycling stability, with about 77 percent capacity retention over 2000 cycles. The structural and chemical evolution of the new battery materials were characterized using the high-resolution microprobe X-ray photoelectron spectroscope, powder X-ray diffraction, focused ion beam/ scanning electron microscope, and aberration corrected scanning transmission electron microscopy at EMSL, a DOE Office of Science user facility. The researchers discovered the solid electrolyte interphase—a protective layer formed on electrodes of batteries as a result of electrolyte decomposition—plays a critical role in reducing consumption of sodium ions in the battery, thereby improving electrode efficiency and long-term cycling stability. This work represents a leap forward in sodium-ion battery development, and together with further optimization of electrolyte and electrode materials, could pave the way for widespread implementation of sodium-ion batteries for large-scale energy-storage applications.

Principal Investigator(s)

Vince Sprenkle
Pacific Northwest National Laboratory
[email protected]

Chongmin Wang
Environmental Molecular Sciences Laboratory
[email protected]

Funding

This work was supported by the Department of Energy (DOE), Office of Science, Office of Biological and Environmental Research, including support of DOE’s Environmental Molecular Sciences Laboratory, a DOE Office of Science user facility; and DOE’s Office of Electricity Delivery and Energy Reliability under contract number 57558.

References

Li, X., P. Yan, M. H. Engelhard, A. J. Crawford, V. V. Viswanathan, C. Wang, J. Liu, and V. L. Sprenkle. 2016. “The Importance of Solid Electrolyte Interphase Formation for Long Cycle Stability Full-Cell Na-Ion Batteries,” Nano Energy 27, 664-72. DOI: 10.1016/j.nanoen.2016.07.030.