Science Vertical II

The promise of enabling high-energy-density batteries has motivated a recent renaissance in the research of metal electrodes with liquid electrolytes. In this context, lithium and sodium have emerged as ideal candidates for anode materials due to their extremely high theoretical capacity (3860 mAhg⁻¹ for Li and 1165 mAhg⁻¹ for Na) and low electrochemical potential (-3.04 V for Li and -2.71 V for Na vs. standard hydrogen electrode). While lithium metal-based chemistries promise to provide higher energy densities, sodium offers critical advantages in terms of material availability, sustainability, and techno-economic aspects.

Despite the exciting potential of utilizing metal electrodes, they are confronted with various fundamental challenges predominantly stemming from the high reactivity of the metal electrodes in liquid electrolytes. During charging, the metal electrode undergoes volume expansions due to non-uniform morphology growth that can lead to dendrite propagation, short-circuit, and potentially culminate in a thermal runaway under extreme circumstances. In addition, the formation of dead metal during discharge influences capacity degradation.

Overall, interface instability and safety are two key barriers that need to be addressed to enable further advancement of metal-based battery systems. Through this science vertical, the fundamental electrochemical-transport-mechanical interactions related to the interface instability of the metal electrode during the plating and stripping processes will be distinctly captured. The mechanistic differences in the interface evolution physics between lithium and sodium electrodes will be comprehensively interrogated.

Critically, the role of interface evolution characteristics including the heterogeneous nature of dendrite-SEI interaction, surface energetics, and dead metal accretion on the safety of the metal anode battery will be analyzed. With the dynamic interaction of electrochemical, chemical, and mechanical characteristics of the metal electrode interface, we hypothesize the associated safety signature to be a strong function of interface evolution, degradation, and heterogeneity.

In addition to the hierarchical interactions related to the metal electrode, this science vertical will also evaluate the mechanisms underlying the degradation, performance, and safety of novel cathode chemistries such as sulfur. The electrolyte transport characteristics, microstructural evolution, and mechanisms, including polysulfide shuttle that are linked to the electrochemical response of the cathode, degradation, and interface stability, will be comprehensively analyzed.