Nickel–Salen-Type Polymer as Conducting Agent and Binder for Carbon-Free Cathodes in Lithium-Ion Batteries
journal contributionposted on 12.12.2018, 00:00 by Cody O’Meara, Mikhail P. Karushev, Iuliia A. Polozhentceva, Sajith Dharmasena, Hanna Cho, Benjamin J. Yurkovich, Sam Kogan, Jung-Hyun Kim
Systematic physical and electrochemical characterizations revealed unique positive multifunction of a polymeric salen-type nickel(II) complex, poly[Ni(CH3-salen)], as an additive for conventional cathodes in lithium-ion batteries. Due to its promising electrochemical and mechanical properties, combined with its unique three-dimensional weblike electron-network structure, the redox-active-organometallic polymer can eliminate conductive carbon and replace a significant portion of the poly(vinylidene fluoride) (PVdF) binder that has been used in conventional LiFePO4 cathodes. By replacing such electrochemically inactive components (i.e., carbon and PVdF), LiFePO4 cathodes with poly[Ni(CH3-salen)] deliver improved energy density compared with the conventional LiFePO4 cathode. Facile electron transfer via large-area contact at polymer/LiFePO4 interfaces significantly accelerates charge-transfer reactions and consequently improves the rate capability of the cathodes. In addition, unlike PVdF, poly[Ni(CH3-salen)] retains steady Young’s modulus values after immersing in an electrolyte solvent, which enhances the mechanical integrity of the cathodes during the cycling of battery cells and thereby improves their cycle life. The unique multifunction of the poly[Ni(CH3-salen)] will be of broad interest for its application in next-generation energy-storage devices.
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next-generation energy-storage devicesLithium-Ion Batteries Systematiccharge-transfer reactionsLiFePO 4 cathoderate capabilityFacile electron transferPVdFelectrochemical characterizationsbattery cellscycle lifeenergy densityConducting Agentweblike electron-network structuresalenredox-active-organometallic polymerconductive carbonLiFePO 4 cathodesCarbon-Free Cathodeslithium-ion batteries