Vibrational and electrochemical studies of pectin—a candidate towards environmental friendly lithium-ion battery development

Abstract

Pectin polymers are considered for lithium-ion battery electrodes. To understand the performance of pectin as an applied buffer layer, the electrical, magnetic, and optical properties of pectin films are investigated. This work describes a methodology for creating pectin films, including both pristine pectin and Fe-doped pectin, which are optically translucent, and explores their potential for lithium-ion battery application. The transmission response is found extended in optimally Fe-doped pectin, and prominent modes for cation bonding are identified. Fe doping enhances the conductivity observed in electrochemical impedance spectroscopy, and from the magnetic response of pectin evidence for Fe³⁺ is identified. The Li-ion half-cell prepared with pectin as binder for anode materials such as graphite shows stable charge capacity over long cycle life, and with slightly higher specific capacity compare with the cell prepared using polyvinylidene fluoride (PVDF) as binder. A novel enhanced charging specific capacity at a high C-rate is observed in cells with pectin binder, suggesting that within a certain rate (∼5 C), pectin has higher capacity at faster charge rates. The pectin system is found as a viable base material for organic–inorganic synthesis studies.