Structure–Property Tailoring of PAN/PVP-Derived Carbon Anodes for Improved Lithium Storage via Carbonization, Fiber Architecture, and C60 Reinforcement

Abstract

Polymer-derived carbon materials provide a versatile platform for developing lithium- ion battery anodes because of their tunable microstructure and electrochemical behavior. In this study, the effect of carbonization temperature on the microstructural evolution and lithium storage performance of carbon materials derived from polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) is investigated. Carbon electrodes were prepared by thermal pyrolysis of the polymer precursors in an Ar atmosphere at different temperatures and then used as working electrodes in lithium-ion half-cells. Electrochemical results indicate that carbonization temperature influences the balance between defect density and graphitic or- dering within the carbon structure. Carbons produced at lower temperatures, like 600°C tend to be more amorphous and exhibit higher lithium storage capacity (stabilized at nearly 380 mAhg−1 for PVP), whereas higher carbonization temperature like 1500°C promote better structural ordering and improved coulombic efficiency but less stabilized capacity at nearly 125 mAhg−1 for PVP and at nearly 175 mAhg−1 for PAN respectively. These ob- servations highlight the important trade-off between capacity and structural ordering in polymer-derived carbon anodes from two different polymer precursors, even after high carbonization temperature. With that, electrospinning is performed to fabricate nanofibrous carbon structures using PAN, PVP, and fullerene (C60)-reinforced systems with better electrochemical performance providing carbonization temperature. This approach is used to explore how fiber morphology and conductive additives affect the electrochemical behavior of the electrodes. Eventually, C60-reinforced PVP fiber mats show a much-improved reversible capacity (at nearly 500 mAhg−1). Overall, this work provides useful insight into designing advanced carbon anodes by controlling microstructure through thermal treatment and precursor architecture.