Characterizing Ion Transport in Poly(Pentyl Malonate) Electrolytes

For decades poly(ethylene oxide) (PEO) has been the leading homopolymer for lithium-ion battery polymer electrolytes. The high conductivity of PEO is demonstrative of its superiority; however PEO also has a large range of applied currents under which it can stably perform. Recently, poly(pentyl malonate) (PPM) has been identified as a homopolymer with ion transport properties comparable to PEO along with stable performance under larger applied currents than that of PEO. This study presents the full electrochemical characterization of electrolytes comprised of PPM and LiTFSI salt across a range of salt concentrations to quantify all necessary parameters to describe ion transport in these electrolytes. With these transport parameters, concentrated solution theory can be used to predict lithium salt concentration gradients within the electrolyte under DC polarization along with the theoretical limiting current with which we can compare the measured values. This full characterization provides a deeper understanding of ion transport and the performance limits of PPM electrolytes.