Voltage Gain in Lithiated Enolate-Based Organic Cathode Materials by Isomeric Effect

Abstract

Li-ion batteries (LIBs) appear nowadays as flagship technology able to power an increasing range of applications starting from small portable electronic devices to advanced electric vehicles. Over the past two decades, the discoveries of new metal-based host structures, together with substantial technical developments, have considerably improved their electrochemical performance, particularly in terms of energy density. To further promote electrochemical storage systems while limiting the demand on metal-based raw materials, a possible parallel research to inorganic-based batteries consists in developing efficient and low-polluting organic electrode materials. For a long time, this class of redox-active materials has been disregarded mainly due to stability issues but, in recent years, progress has been made demonstrating that organics undeniably exhibit considerable assets. On the basis of our ongoing research aiming at elaborating lithiated organic cathode materials, we report herein on a chemical approach that takes advantage of the positive potential shift when switching from para to ortho-position in the dihydroxyterephthaloyl system. In practice, dilithium (2,3-dilithium-oxy)-terephthalate compound (Li4C8H2O6) was first produced through an eco-friendly synthesis scheme based on CO2 sequestration, then characterized, and finally tested electrochemically as lithiated cathode material vs. Li. This new organic salt shows promising electrochemical performance, notably fast kinetics, good cycling stability and above all an average operating potential of 2.85 V vs. Li(+)/Li(0) (i.e., +300 mV in comparison with its para-regioisomer), verifying the relevance of the followed strategy.

Perspectives in Lithium Batteries

“…142,143 For instance, the standard one-electron potentials of various ortho-quinone derivatives can range from wÀ0.5 to more than 1 V versus NHE, 144 which is quite larger than the possibility of tuning the formal potential through polyanion substitutions in Fe-based 3-D NASI-CON structures by the inductive effect. The opposite situation occurs with system B (or n-type) that exhibits negative charges balanced by cations.…”

On the improved electrochemistry of hybrid conducting-redox polymer electrodes

“…As for the capacity extraction, Poizot et al . 28 postulated that structural aspects can induce the redox process to be limited to one-electron redox per BQ instead of the theoretical two. Furthermore, even though polyaniline is the oldest known synthetic conjugated polymer, its molecular structure is still matter of debate.…”

Structure-Property of Metal Organic Frameworks Calcium Terephthalates Anodes for Lithium-ion Batteries

“…Poizot and coworkers find that isomeric effect in dilithium (2,3-dilithiumoxy)-terephthalate compound (Li 4 C 8 H 2 O 6 ) offers a voltage gain [19]. Yasuda et al discovered that 2,6-naphthalene dicarboxylate dilithium with higher ordering structure has better electrochemical performance for provding more efficient electron and ion pathways [4].…”