Nancy L. Dietz Rago

A high performance separator with improved thermal stability for Li-ion batteries

A thermally stable separator based on a poly(phenylene oxide)/SiO2 composite is prepared using a dry phase inversion method. The separator endures up to 250 °C without obvious thermal deformation. A LiNi1/3Mn1/3Co1/3O2/graphite cell using the composite separator showed excellent cycling performance, especially at high C-rates.

An organophosphine oxide redox shuttle additive that delivers long-term overcharge protection for 4 V lithium-ion batteries

Redox shuttle additives are used to protect Li-ion batteries from overcharge. Increased operating voltage requires striking a balance between a high redox potential and electrochemical stability. 1,4-Bis[bis(1-methylethyl)phosphinyl]-2,5-dimethoxybenzene (BPDB) exhibits a redox potential of 4.5 V vs. Li/Li+ and provides stable overcharge protection for 4 V cells delivering 95 cycles of 100% overcharge ratio.

Improved performance through tight coupling of redox cycles of sulfur and 2,6-polyanthraquinone in lithium–sulfur batteries

Lithium–sulfur (Li–S) batteries offer high theoretical capacity and energy density; however, complex nanoengineered cathodes have been required to suppress the unwanted polysulfide shuttling. The textural complexity of such electrodes hinders detailed understanding of their function, impeding the development of new materials. In this report, the redox-active polymer 2,6-polyanthraquinone (PAQ) was incorporated into the cathode. The presence of this polymer improves capacity retention in galvanostatic cycling and inhibits Li corrosion and S deposition. We show that redox reactions of this polymer are strongly coupled to the S redox cycle and hypothesize that the observed improvements in the performance originate from the electrocatalytic inhibition of polysulfide shuttling in this system.