Surface Controlled Pseudo-Capacitive Reactions Enabling Ultra-Fast Charging and Long-life Organic Lithium Ion Batteries

To develop ultra-fast charging and long-life lithium ion batteries, a surface-controlled pseudo-capacitive reaction mechanism for high-performance organic lithium ion batteries is developed based on a coaxial nanocomposite of active anthraquinone-based Covalent Organic Framework (AQ-COF) and carbon nanotubes. AQ-COF was grown on the surface of carbon nanotubes (AQ-COF@CNTs) through an in-situ polymerization to improve the conductivity and to facilitate the electrochemical properties. AQ-COF grown on CNTs exhibited excellent rate performance and was found to retain 76% of its initial capacity at current density of 5,000 mAg-1 (33C), and even retained 48% at ultra-high current density of 10,000 mAg-1 (66.7 C). Furthermore, under long term cyclic performance investigations, the AQ-COF@CNTs based cathode retained 100 % of its initial capacity even after 3000 charge–discharge cycles. We further evaluated the charge storage mechanism and found that pseudocapacitance arising from surface-controlled redox reactions, coupled with excellent charge-transfer properties owing to the conductive CNTs network and facilitated by large surface area of active material, is mainly responsible for this excellent rate and cyclic performance .