PNNL

Abstract

Several different carbons have been systematically investigated in high voltage lithium ion batteries. It was founded that the higher surface area, the more parasitic reactions initiating from different onset voltages. A closer inspection reveals that for the low surface area carbon such as Super P, PF6- ions intercalate into carbon structure above 4.7 V contributing partial capacity. For high surface area carbon, in addition to the electrolyte decomposition, the oxidation of functional groups at high voltage further increases the irreversible capacities and Li+ ion consumption. Coulombic efficiency, reversible capacity and cycling stability observed by using different carbon additives are successfully correlated with their structure and surface chemistry providing information for predictive selection of carbons in different energy storage systems.