Key Takeaways & Executive Findings
- •• CTR-derived carbon materials were synthesized via direct carbonization at 700–1000°C, converting hazardous solid waste into valuable anodes for potassium-ion batteries. • The optimal CTRC-900H electrode delivered a high reversible capacity of 265.6 mAh·g−1 at 50 mA·g−1 and retained 93.8% capacity after 100 cycles, demonstrating excellent cycling stability. • Electrochemical analysis revealed that potassium storage is dominated by surface-induced capacitive processes, following an 'adsorption–weak intercalation' mechanism. • This work provides a sustainable, low-cost strategy for high-value-added utilization of coal tar residue, addressing both waste management and energy storage challenges.
Abstract
Carbon materials are widely recognized as highly promising electrode materials for various energy storage system applications. Coal tar residues (CTR), as a type of carbon-rich solid waste with high value-added utilization, are crucially important for the development of a more sustainable world. In this study, we employed a straightforward direct carbonization method within the temperature range of 700–1000°C to convert the worthless solid waste CTR into economically valuable carbon materials as anodes for potassium-ion batteries (PIBs). The effect of carbonization temperature on the microstructure and the potassium ions storage properties of CTR-derived carbons (CTRCs) were systematically explored by structural and morphological characterization, alongside electrochemical performances assessment. Based on the co-regulation between the turbine layers, crystal structure, pore structure, functional groups, and electrical conductivity of CTR-derived carbon carbonized at 900°C (CTRC-900H), the electrode material with high reversible capacity of 265.6 mAh·g−1 at 50 mA·g−1, a desirable cycling stability with 93.8% capacity retention even after 100 cycles, and the remarkable rate performance for PIBs were obtained. Furthermore, cyclic voltammetry (CV) at different scan rates and galvanostatic intermittent titration technique (GITT) have been employed to explore the potassium ions storage mechanism and electrochemical kinetics of CTRCs. Results indicate that the electrode behavior is predominantly governed by surface-induced capacitive processes, particularly under high current densities, with the potassium storage mechanism characterized by an “adsorption–weak intercalation” mechanism. This work highlights the potential of CTR-based carbon as a promising electrode material category suitable for high-performance PIBs electrodes, while also provides valuable insights into the new avenues for the high value-added utilization of CTR.
1. Introduction
Along with economic growth and modernization, the quantity and variety of the solid waste have increased dramatically, which makes waste management one of the most critical worldwide challenges [1–2]. Improper and inefficient waste disposal can cause a range of environmental issues, including pollution, ecosystem destruction, natural resources depletion, and human health risks, thus compelling governments to allocate greater resources towards environmental remediation [3]. Simultaneously, the depletion of traditional fossil fuels and the escalating demand for energy urgently calls for the development of renewable resources [4]. Consequently, enhancing the efficiency of solid waste treatment and recycling emerges as a critical strategy for the sustainable development of the environment and energy.
Coal tar residue (CTR), a type of hazardous waste produced from post-processing of coal coking or gasification, primarily comprises solid particles such as pulverized coal, coke powder, and inorganic minerals, along with an abundance of tar compounds [5]. Due to its high fixed carbon content and condensed polycyclic aromatic hydrocarbons, CTR promises as a secondary energy source [6]. The traditional industrial utilizations of CTR are as fuel and for coal-bending coking. Recent studies on CTR have also focused on the separation and characterization of its tar components [7–8]. In terms of utilization technology, CTR have been utilized to generate activated carbon (AC) with developed pore size, high surface area, and superior adsorption performance. Our previous study employed ethyl acetate to extract CTR and successfully prepared the residue into powdered activated carbon for adsorption of phenol in wastewater [9]. Gao et al. [10] prepared mediate quality AC from CTR using H3PO4 as the activating agent, and they studied the effect of H3PO4 on the activation energy of pyrolysis reaction by kinetic model fitting. Wang et al. [11] synthesized the CTR-based oxygen-rich AC and then compounded it with Fe3O4 nanoparticles. The prepared Fe3O4/AC composite exhibited high specific capacitance for supercapacitors. These studies confirmed that CTR has the potential for high value-added conversion.
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Zhonghua Lu, Jun Shen, Xin Zhang, Lingcong Chao, Liang Chen, Ding Zhang, Tao Wei, Shoudong Xu (2025). From waste to wealth: Coal tar residue derived carbon materials as low-cost anodes for potassium-ion batteries. Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报). https://doi.org/10.1007/s12613-024-2930-8
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Frequently Asked Questions
What is the main objective of this study?
The study aims to convert coal tar residue (CTR), a hazardous solid waste, into valuable carbon materials as low-cost anodes for potassium-ion batteries (PIBs), thereby addressing waste management and energy storage challenges.
How were the carbon materials synthesized?
The carbon materials were synthesized via a straightforward direct carbonization method at temperatures ranging from 700°C to 1000°C, without the need for additional activation agents.
What are the key electrochemical performance metrics of the optimal material?
The optimal material, CTRC-900H, exhibited a high reversible capacity of 265.6 mAh·g−1 at 50 mA·g−1, 93.8% capacity retention after 100 cycles, and remarkable rate performance.
What is the potassium storage mechanism of the CTR-derived carbons?
The potassium storage mechanism is characterized as an 'adsorption–weak intercalation' mechanism, predominantly governed by surface-induced capacitive processes, especially at high current densities.
What is the significance of this work?
This work highlights the potential of CTR-based carbon as a promising electrode material for high-performance PIBs, while also providing a sustainable route for the high value-added utilization of coal tar residue, contributing to both environmental remediation and renewable energy development.
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