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In the continuing challenge to find new routes to improve the performance of commercial lithium ion batteries cycling in alkyl carbonate-based electrolyte solutions, original designs, and new electrode materials are under active worldwide investigation. Our group has focused on the electrochemical behavior of a new generation of nanocomposite electrodes showing improved capacities (up to 3 times the capacity of conventional electrode materials). However, moving down to 'nanometric-scale' active materials leads to a significant increase in electrolyte degradation, compared to that taking place within commercial batteries. Postmortem electrolyte studies on experimental coin cells were conducted to understand the degradation mechanisms. Structural analysis of the organic degradation products were investigated using a combination of complementary high-resolution mass spectrometry techniques: desorption under electron impact, electrospray ionization, and gas chromatography coupled to a mass spectrometer equipped with electron impact and chemical ionization ion sources. Numerous organic degradation products such as ethylene oxide oligomers (with methyl, hydroxyl, phosphate, and methyl carbonate endings) have been characterized. In light of our findings, possible chemical or electrochemical pathways are proposed to account for their formation. A thorough knowledge of these degradation mechanisms will enable us to propose new electrolyte formulations to optimize nanocomposite-based lithium ion battery performance.

The article explains the synthesis, characterization, as well as the properties of various ethoxycarbonyl-based organic electrodes used in lithium batteries. Organic components are shown to lead to significant enhancement of the performance of the batteries.

A novel and large family of boron esters of general formula Y-C((C[H.sub.2]O)([Z.sub.1]O)([Z.sub.2]O))B is described whose Lewis acidity is curbed from geometrical constraint and is tuned by electron affinity either so as to partially or fully dissolve the compounds both in battery solvent EC/DMC and in DMF. The extreme simplicity of synthesis and variability of boron-based anion carriers are a valuable addition to coordination science and also a step forward to improve present battery systems.