ae9b01339_si_001.pdf (2.31 MB)
Negative Redox Potential Shift in Fire-Retardant Electrolytes and Consequences for High-Energy Hybrid Batteries
journal contribution
posted on 2019-10-17, 21:03 authored by Bruno Ernould, Louis Sieuw, Gabriella Barozzino-Consiglio, Jean-François Gohy, Alexandru VladFire-retardant
electrolyte chemistries have attracted great attention
given their potential to solve the grand challenges of alkali-ion
batteries: safety, use of metallic anodes, and anodic stability. Whereas
extensive analysis and correlations are drawn to explain their unusual
electrochemical behavior, one essential property, their effects on
redox potentials of battery components (redox potential shift) pervasively
lack a strict description and quantification. Here we show that the
strong solvation of lithium cations by organic phosphates, the widely
used flame-retardant constituents, induces a negative redox potential
shift by as much as 500 mV. We demonstrate that the redox potential
shift is characteristic of Li-cation (de)solvation processes whereas
it is negligible for other processes. This has important consequences
for high energy hybrid battery concepts such as high voltage dual-ion
graphite or organic batteries. These findings also shine a different
light on the enhanced anodic stability of these nonconventional battery
electrolyte formulations.