Development of Organic Electrode Materials for Li-Ion Batteries

Nowdays electrode materials of lithium batteries are mainly constituted by inorganic compounds based on transition metals such as cobalt, nickel or manganese. Although their performances are satisfying, these materials present several important drawbacks. Indeed these compounds are expensive and present high environmental footprints because they are prepared due to energy-consuming techniques from rare mineral precursors. Moreover, some metals are toxic and often hard to recycle. Eventually their reactivity leads to safety issues in abusive conditions. N-type organic electroactive compounds such as quinone, polyimide or carboxylate salts offer a cost-effective and environmental friendly alternatives to conventional electrode materials for electrochemical storage. Interestingly these products can be prepared using (green) organic and polymer chemistry from low cost (bio-based) precursors. Moreover these compounds are easy to recycle or reuse at their end of life. But until now, their implementation in full prototypes is still challenging especially due to their high solubility in liquid electrolytes but also related to their low electronic conductivity and the lack of lithium source. In order to demonstrate the interest of organic battery technology, several approaches have been studied at CEA at material, electrode and cell levels and will be presented. First new n-type structures based on quinones have been identified and synthesized targeting organic materials for positive electrode with high voltage (>3V vs Li + /Li) and high specific capacity (>100mAh.g -1 ). In particular a lithiated air-stable Mg(Li 2 )-p-DHT (magnesium (2,5-dilithium-oxy)-terephthalate) compound has been developed and produced at pilot scale in collaboration with CNRS-IMN. Moreover some works about electrode formulations of carboxylate and quinone based materials lead to the preparation of viable electrodes with high active material loading (>1mAh.cm -2 ) and low carbon content (<10%wt) and several meters of double-sided electrodes have been coated on pre-industrial equipment. Finally several full Li-ion prototypes (multi-layer prismatic cell) have been assembled with Mg(Li 2 ) - p-DHT based electrode versus graphite and the electrochemical performances are very promising with high capacity retention at high C-rate (>70% at 2C) or after 50 cycles (>95% of initial capacity) and a proven energy density of 60Wh.kg -1 at cell level. Our last studies about the influence of the nature of electrolyte will also be presented.