(Invited) Advanced Carbons for Stable Li, Na and K Metal Battery Anodes

Metal batteries (MBs) are viewed as highly promising "Beyond Li" energy storage systems with up to twice the energy of commercial LIBs. This includes lithium metal batteries (LMBs), sodium metal batteries (SMBs) and potassium metal batteries (KMBs). There are still major technical challenges with all MBs, however, that prevent commercial adoption. An unstable solid electrolyte interphase (SEI) promotes growth of filament-like dendrites at the anode, leading to electrical shorts and associated safety hazards. This presentation discusses several electrode architecture design examples where carbons with tuned structure chemistry and morphology are employed to (i) create a "philic" surface, thereby promoting electrochemical metal wetting on the current collector, or (ii) form a "phobic" membrane, replacing the unstable native SEI with a more stable artificial one. It is demonstrated that the design rules for cases (i) and (ii) are fundamentally different, and that in addition to wetting of the metal, wetting of the electrolyte has to be controlled. A strong correlation between electrolyte wetting, the SEI structure and uniformity, and metal plating/stripping stability was discovered. This presentation also covers the use of tailored carbons for MB cathodes, highlighting S and SeS -based systems that display covalent bonding and closed pore encapsulation. In addition to Li, covalent/close pore carbon hosts stabilize the much more challenging K and Na systems, suppressing the cycling-induced parasitic shuttle and electrode disintegration. The presented findings were recently published as a series of articles in Advanced Materials and Advanced Energy Materials.