Understanding the Degradation Mechanisms in Phosphorous-Carbon Hybrid Anodes for Sodium-Ion Batteries

Non-Technical Abstract

Electrical energy storage is a key component of the renewables-friendly future power grid with high-energy efficiency, stability, and resilience. Sodium ion batteries have a significant advantage over widely used Lithium ion batteries, owing to the low cost and abundance of sodium precursor. Phosphorus-based materials are promising as anodes for sodium ion batteries due to their high capacity and low cost. However, similar to alloy anodes in lithium ion batteries, phosphorus undergoes ~300% volume change during charge/discharge, leading to pulverization of the active materials, unstable growth of the solid electrolyte interphase, and poor cyclability. With the support of the Solid State nad Materials Chemistry program, this research project strives to bring low-cost, high-performance, long-cycling sodium ion batteries closer to real-world applications by understaning the degradation mechanisms of phosphorus-based anode materials. Such batteries would enable greater integration of intermittent renewable power sources such as wind and solar, decrease dependence on fossil fuels, and improve the overall efficiency, stability, and resilience of the power grid. The research project also enhances involvement of women and minorities in science and engineering, and stimulates the interests of students at Penn State in the fast-evolving research field of nanostructured energy storage materials.

Technical Abstract

The research objective of this award is to uncover the underlying mechanisms of electro-chemically driven mechanical degradation in phosphorus-carbon hybrids as anode materials for sodium ion batteries through an integrated experimental-modeling approach. Experimentally, in situ TEM studies allow atomic-scale observation of phase transformation and failure mechanisms. Combined with the low-cost, scalable synthesis methods and advanced full-cell battery testing and characterization, the experimental studies enable the research team to build an atomic-scale picture of microstructure, morphology, and composition evolution of the hybrids during electrochemical cycling. The proposed multiscale models seamlessly integrate with the experimental characterizations to identify the leading degradation mechanisms and accordingly optimize the material designs. The integrated experimental-modeling approach helps foster transformative progress for developing high-performance energy storage materials.