Potentiometric titration

Battery (electricity)

Chemical physics

Lithium (medication)

Statistics

Materials science

Solvation

Endocrinology

Energy (signal processing)

Psychiatry

Power (physics)

Inorganic chemistry

Physical chemistry

Thermodynamics

Physics

Organic chemistry

Psychology

Mathematics

Environmental chemistry

Concentration cell

Internal medicine

Analytical Chemistry (journal)

Medicine

Chemistry

Electrode

Anode

Electrolyte

Journal of the American Chemical Society

The electrolyte plays a critical role in lithium-ion batteries, as it impacts almost every facet of a battery's performance. However, our understanding of the electrolyte, especially solvation of Li+, lags behind its significance. In this work, we introduce a potentiometric technique to probe the relative solvation energy of Li+ in battery electrolytes. By measuring open circuit potential in a cell with symmetric electrodes and asymmetric electrolytes, we quantitatively characterize the effects of concentration, anions, and solvents on solvation energy across varied electrolytes. Using the technique, we establish a correlation between cell potential (Ecell) and cyclability of high-performance electrolytes for lithium metal anodes, where we find that solvents with more negative cell potentials and positive solvation energies—those weakly binding to Li+—lead to improved cycling stability. Cryogenic electron microscopy reveals that weaker solvation leads to an anion-derived solid-electrolyte interphase that stabilizes cycling. Using the potentiometric measurement for characterizing electrolytes, we establish a correlation that can guide the engineering of effective electrolytes for the lithium metal anode.

Potentiometric Measurement to Probe Solvation Energy and Its Correlation to Lithium Battery Cyclability