CoS2 is a promising anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity. However, its practical application is hampered by severe volume expansion during cycling. In this study, fluorine-doped carbon-coated CoS2 (F-CoS2@C) was synthesized via NaCl template-assisted carbon coating using petroleum-derived pyrolyzed fuel oil, followed by CF4 plasma treatment. The proposed method of synthesis enables control of the carbon layer thickness, formation of a void structure, and introduction of fluorine functional groups. F–CoS2@C delivered 295 mAh/g at 5 A/g and retained 375 mAh/g after 500 cycles at 1 A/g. The enhanced electrochemical performance is attributed to the void carbon structure and fluorine-induced interfacial stabilization. The carbon structure increased electrolyte penetration and electrical conductivity, and mitigated volume changes. Fluorine doping promoted the formation of a LiF-rich solid electrolyte interphase layer and enhanced the electronic transport by semi-ionic C-F bonds. This study offers a promising strategy for the development of transition metal sulfide/carbon composites as high-performance LIB anodes.

In this study, we upcycled waste polyethylene (PE) foam into a hard carbon anode material for sodium-ion batteries (SIBs) via sulfonation and subsequent carbonization. Following an optimized sulfonation process (100 °C, 24 h), the sample carbonized at 800℃ (PE_C800) demonstrated the best performance, showing a high reversible capacity of 180 mAh·g− 1 at 0.1 C, excellent rate capability, and long-term cycling stability (93.3% retention after 100 cycles). Structural analysis revealed this sample possessed a hierarchical porous structure and an interlayer spacing (0.388 nm), suitable for Na+ insertion. Through cyclic voltammetry (CV) kinetic analysis and ex-situ Raman spectroscopy, the sodium storage was determined to follow an “adsorption-insertion model”, combining surface adsorption and interlayer insertion. This work presents a practical route for converting plastic waste into high performance energy storage materials.

The demand for energy storage devices with both high power and energy density has risen significantly because of growing global environmental concerns. Lithium metal capacitors (LMCs) have emerged as promising candidates for nextgeneration energy storage systems by addressing the low energy density limitations of conventional electric double-layer capacitors (EDLCs). However, lithium dendrite formation and volume expansion in lithium metal anodes pose major challenges, leading to performance degradation and safety risks. In this study, a three-dimensional nano-perforated graphene (3-D NPG) with SnO₂ composite as an advanced anode material for LMCs. The 3-D NPG improved electrochemical performance by offering a high surface area, reducing local current density, and mitigating volume expansion. Furthermore, the lithiophilicity of SnO₂ facilitated lithium deposition by effectively reducing the lithium nucleation overpotential. The composite exhibited the lowest lithium nucleation overpotential (39.44 mV), along with a superior rate capability and remarkable cycle stability, retaining 88.5% of its capacity after 10,000 cycles at 2 A/g. The improved lithium-ion transport and lithiophilicity of the composite significantly suppressed dendritic lithium growth, thereby enhancing the electrochemical performance of LMCs. These results demonstrate the potential of 3-D SnO₂/NPG as a next-generation anode material for high-performance energy storage applications.

Porous hard carbon has recently gained attention as an anode material for KIB because of its superior potassium ion storage performance. In this study, an efficient method for producing polyethylene-based hollow porous carbon is presented. Partial sulfonation was applied, and the porosity of the resulting carbon material was regulated by the sulfonation time. A hollow structure with the high specific surface area of 173.3 m2/g was achieved via partial sulfonation and carbonization without additional activation. Using polyethylene (PE)-based porous carbon as an anode material for KIB, a high specific discharge capacity of 187 mAh/g and excellent rate capability at 1000 mA/g were achieved. Moreover, potassium-ion storage mechanisms were identified and compared with those of non-porous PE-based carbon anodes. This study provides an effective method for preparing porous PE-based carbon with superior energy storage performance.

The high theoretical capacity of transition metal-based compounds makes them promising candidates for lithium-ion battery (LIB) anodes. Among them, iron selenide (FeSe2) has attracted considerable interest because of its excellent electrical conductivity and superior lithium storage capacity. However, pristine FeSe2 suffers from rapid capacity fading and structural instability during repeated cycling. Thus, this study used a facile solvothermal method to synthesize a FeSe2@rGO composite with enhanced structural integrity and electrical conductivity. By incorporating reduced graphene oxide (rGO), the composite demonstrated improved charge transfer kinetics and mechanical robustness. Morphological and structural characterizations were performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy analyses (XPS), which confirmed the successful formation of the composite and its uniform distribution. Electrochemical properties were evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge, long-term cycling, and electrochemical impedance spectroscopy. The optimized FeSe2@rGO electrode delivered a high reversible capacity of 971.95 mAhg-1 at 500 mAg-1 after 350 cycles. The underlying charge storage mechanism was investigated using scan rate-dependent CV, which revealed a dominant capacitivecontrolled contribution at higher scan rates. The study findings indicate that the FeSe2@rGO composite can serve as a high-performance anode material with excellent cycling stability and rate capability, providing a viable strategy for the development of advanced LIBs.

In this study, an anode composite material was fabricated by embedding spherical carbon-coated nanosilicon (Si@C) into a layered carbon-coated silicon (L-Si/C) to enhance the capacity and stability of silicon-based lithium-ion batteries. The L-Si/C material was obtained by reacting CaSi2 through a CO₂-assisted carbonization process, followed by removal of the CaCO3 byproduct via HCl etching. Si@C particles, prepared using polydopamine as a carbon precursor, were uniformly embedded in the L-Si/C via ultrasonic treatment. The physical properties of the prepared anode composites were analyzed using HR-SEM, EDS, XRD, and BET. The electrochemical performances were investigated using 1 M LiPF6 in EC:DEC (1:1 vol%) with 10 wt% FEC as the electrolyte, through charge–discharge cycling, rate capability tests, electrochemical impedance spectroscopy (EIS), and differential capacity (dQ/dV) analysis. L-Si/C exhibited the best electrochemical performance under the thermal treatment condition of 720 °C and a CO2 flow rate of 100 sccm. In addition, the application of ultrasonic treatment improved structural stability and rate capability. Consequently, the S_L-Si/C + Si@C-2 exhibited a high initial discharge capacity of 2700.7 mAh/g at 0.1 C and a capacity of 617.4 mAh/g at a high rate of 6 C.

Recent advancements in 2D graphene materials highlight their versatile applications in electronics, clean energy, medicine, and other fields due to their exceptional properties and ease of fabrication. The current study investigates the preparation of reduced graphene oxide (RGO) through the thermal exfoliation of graphite oxide under an air atmosphere at varying temperatures (200–500 °C) and further examines its suitability as an anode for lithium-ion (Li-ion) batteries. The extent of reduction of functional groups, exfoliation, and other physical changes is analyzed by XRD, SEM, XPS, BET, and Raman studies, which show that the reduction of functional groups and surface area increases with increasing exfoliation temperature. The RGO electrodes are subjected to electrochemical studies, including cyclic voltammetry and charge–discharge cycling at various current densities, which demonstrate varying discharge capacities for RGO samples prepared at different temperatures. The RGO exfoliated at 400 °C delivered the maximum capacity, indicating that this temperature is optimal for the thermal preparation of RGO. This material shows potential for use as an anode in Li-ion batteries.

The constituents of coal tar pitch (CTP) significantly impact the wettability of calcined coke (CC) and the performance of prebaked anodes (PA) used in aluminum electrolysis. However, balancing wettability and carbon residue within CTP remains a central challenge in material applications. In addition, limited pore permeability and structural stability in these composites hinder the effective utilization of PA. Enhancing CTP fluidity is crucial for overcoming these challenges. In this work, a novel method was developed to modify CTP utilizing various coal tar fractions, enabling controlled modulation of CTP composition and wettability. Incorporating different fractions allowed for substantial control over interfacial bonding and pore structure. The chemical composition, functional groups, and elemental content of the CTP were analyzed via X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and proton nuclear magnetic resonance (1H NMR). Subsequently, systematic comparisons of PA materials produced from different CTP formulations demonstrated improved wettability and enhanced mechanical properties. Moreover, DFT calculations were performed to compare the adsorption energies of small molecules from different coal tar fractions with coke, reflecting the interaction strength between the molecules and the solid surface. Using micro-computed tomography (μ-CT), the refined pore structure was examined, resulting in a PA composite with an optimized balance of high strength and toughness.

Hard carbon's excellent performance and affordability made it an ideal anode material for sodium-ion batteries. However, hard carbons derived directly from lignin often exhibit poor performance. Optimizing the synthesis process presents a valuable strategy for enhancing performance. In this study, we optimize the synthesis process to minimize costs while integrating green chemistry principles to mitigate environmental impact. Sodium lignosulfonate-formaldehyde resin-derived hard carbon is produced using a simple, low-cost pyrolysis technique involving multiple temperature stages. This process enhances the material's structural stability and electrochemical performance. X-ray diffraction (XRD) and Raman spectroscopy analysis show that higher pyrolysis temperatures lead to a distinct peak, which improves electronic conductivity. In contrast, lower temperatures result in chaotic structural formations. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) image analyses reveal that the resulting material has a porous structure with unique chemical properties. Tested for 200 cycles at a current density of 50 mA g− 1, the materials exhibited specific capacities of 332.24 mAh g− 1, 180.3 mAh g− 1, and 105.6 mAh g− 1, respectively, for LSHC-1400, LSHC-1200, and LSHC-1000. The promising results can be attributed to the unique porous structure and inherent chemical properties of the lignosulfonate precursor, which enhance the transport and storage of sodium ions. This study highlights the critical role of the synthesis method in determining the sodium storage capacity of the carbon anode in sodium-ion batteries, encouraging further exploration and optimization in this area.

In this paper, the structural optimization and experimental validation of lightweight, high stiffness rollers for roll-to-roll(R2R) processing of lithium metal electrodes are presented. Precise dimensional control of electrode thickness below 50㎛ is essential for next-generation high energy density batteries, yet elastic recovery during rolling hinders the achievement of target specifications. To address this challenge, finite element(FE) analysis was employed to determine the optimal rolling gap and roller geometry, and the results were verified through R2R experiments. Simulations indicated that a rolling gap of 153㎛ yielded a final sheet thickness of about 49.6㎛, meeting the design requirement. Experimental results confirmed the validity of the numerical model, with thickness measurements deviating less than ±10% from FE analysis predictions. These findings demonstrate that the proposed roller design not only ensures thickness precision but also improves system efficiency, offering practical guidelines for scalable lithium metal electrode manufacturing.

Polyethylene (PE) is one of the most widely used plastics, and vast amounts of waste PE are either buried or incinerated, leading to environmental concerns. Significant research efforts have focused on converting waste PE into carbon materials, particularly as carbon anodes for lithium-ion batteries (LIBs). However, most previously developed PE-based carbon anodes have underperformed compared to graphite-based commercial anode materials (CAM). In this study, LIB anode materials were prepared based on both commercial high-density polyethylene (CPE) and waste high-density polyethylene (WPE). Through thermal oxidative stabilization and high-temperature graphitization, both CPE and WPE were successfully transformed into highly crystalline carbon materials comparable to CAM. However, despite the high crystallinity, both CPE and WPE derived carbon contained significant number of fine particles and exhibited a broad particle size distribution. When used as an anode for LIBs, fine particles led to unwanted side reactions, resulting in an initial coulombic efficiency (ICE) of around 85%, which is lower than the ICE value of 92.5% observed in CAM. To tackle the low ICE problem, recarbonization after coal tar (CT) coating was adopted as a mean to induce secondary particle formation. After CT coating, the average particle size increased, and the size distribution became narrower. Although CT coating reduced the crystallinity slightly, the overall level remained comparable to that of CAM. As a result, the CT-coated graphitized CPE (GCPE@10CT) and CT-coated graphitized WPE (GWPE@10CT) exhibited performance comparable to CAM as LIB anodes, achieving an ICE of over 93% and a capacity of approximately 349 mAh g− 1.

This study explores the development and characterization of hard carbon anodes for sodium-ion batteries produced from waste coffee grounds, synthesized at both 1000 °C and 1500 °C. Importantly, this work highlights the potential of using biomass-derived hard carbons as sustainable and effective material for anode for sodium-ion batteries, contributing to the advancement of energy storage systems with increasing global demands for environmentally friendly and cost-effective technologies. The research focuses on the electrochemical performance of these hard carbons, examining how different carbonization temperatures impact their structural and electrochemical properties. Utilizing advanced analytical methods, the structural changes correlating with temperature increase were identified, including modifications in carbon atom arrangements, which significantly influence the electrochemical behaviors of the hard carbons. Our research specifically focuses on how the structural differences affect the division of capacity contribution from sloping region (above 0.1 V) and plateau regions (below 0.1 V). Electrochemical test results revealed that hard carbon with higher degree of order and reduced microstructural defects, demonstrated improved capacity values. At the same time, the highly ordered hard carbon exhibits drastic capacity loss upon increasing of current densities. The results from this study not only advance our understanding of hard carbons but also open pathways for the future exploration of hard carbons for additional improvements.

Si-based anodes are promising alternatives to graphite owing to their high capacities. However, their practical application is hindered by severe volume expansion during cycling. Herein, we propose employing a carbon support to address this challenge and utilize Si-based anode materials for lithium-ion batteries (LIBs). Specifically, carbon supports with various pore structures were prepared through KOH and NaOH activation of the pitch. In addition, Si was deposited into the carbon support pores via SiH4 chemical vapor deposition (CVD), and to enhance the conductivity and mechanical stability, a carbon coating was applied via CH4 CVD. The electrochemical performance of the C/Si/C composites was assessed, providing insights into their capacity retention rates, cycling stability, rate capability, and lithium-ion diffusion coefficients. Notably, the macrostructure of the carbon support differed significantly depending on the activation agent used. More importantly, the macrostructure of the carbon support significantly affected the Si deposition behavior and enhanced the stability by mitigating the volume expansion of the Si particles. This study elucidated the crucial role of the macrostructure of carbon supports in optimizing Si-based anode materials for LIBs, providing valuable guidance for the design and development of high-performance energy-storage systems.

In this study, carbon coating was carried out by physical vapor deposition (PVD) on SiOx surfaces to investigate the effect of the deposited carbon layer on the performance of lithium-ion batteries as a function of the asphaltene content of petroleum residues. The petroleum residue was separated into asphaltene-free petroleum residue (ASF) and asphaltene-based petroleum residue (AS) containing 12.54% asphaltene by a solvent extraction method, and the components were analyzed. The deposited carbon coating layer became thinner, with the thickness decreasing from 15.4 to 8.1 nm, as the asphaltene content of the petroleum residue increased, and a highly crystalline layer was obtained. In particular, the SiOx electrode carbon-coated with AS exhibited excellent cycling performance with an initial efficiency of 85.5% and a capacity retention rate of 94.1% after 100 cycles at a current density of 1.0 C. This is because the carbon layer with enhanced crystallinity had sufficient thickness to alleviate the volume expansion of SiOx, resulting in stable SEI layer formation and enhanced structural stability. In addition, the SiOx electrode exhibited the lowest resistance with a low impedance of 23.35 Ω, attributed to the crystalline carbon layer that enhanced electrical conductivity and the mobility of Li ions. This study demonstrated that increasing the asphaltene content of petroleum residues is the simplest strategy for preparing SiOx@C anode materials with thin, crystalline carbon layers and excellent electrochemical performance with high efficiency and high rate performance.

With the emergence of the new energy field, the demand for high-performance lithium-ion batteries (LIBs) and green energy storage devices is growing with each passing day. Carbon nanotubes (CNTs) exhibit tremendous potential in application due to superior electrical and mechanical properties, and the excellent lithium insertion properties make it possible to be LIBs anode materials. Based on the lithium insertion mechanism of CNTs, this paper systematically and categorically reviewed the design strategies of CNTs-based composites as LIBs anode materials, and summarized in detail the enhancement effect of CNTs fillers on various anode materials. More importantly, the superiorities and limitations of various anode materials for LIBs were evaluated. Finally, the research direction and current challenges of the industrial application of CNTs in LIBs were prospected.

탄소중립을 달성하기 위해 이산화탄소를 포집, 활용, 저장하는 CCUS (carbon capture, utilization, and storage) 기 술이 주목받고 있다. 본 연구에서는 광물 탄산화 공정을 통해 이산화탄소를 탄산염으로 고정하고, 이를 전이금속 탄산염 기반 리튬이온배터리 (LIB) 음극재로 적용하였다. CO2를 탄산염으로 고정후, 이를 이용해 FeCO3를 제작하고, rGO와 PVP와 복합 화하여 음극활물질에 적용하였다. rGO는 전기전도도를 높이고 입자의 응집을 방지해 부피 팽창을 완화했으며, PVP는 계면 활성제로서 입자 표면을 안정화하여 구조적 안정성을 강화하였다. FeCO3-PVP-rGO 복합체 기반한 음극재에 대한 전기화학 테스트를 진행한 결과, FeCO3/rGO 복합체는 1,620 mA/g의 전류 밀도에서 50 사이클 이후에도 400 mAh/g의 용량을 유지하 였다. 본 연구는 CO2를 고부가가치 배터리 소재로 전환하여 차세대 에너지 저장 기술에 기여할 가능성을 시사한다.

Mesocrystals are macroscopic structures formed by the assembly of nanoparticles that possess distinct surface structures and collective properties when compared to traditional crystalline materials. Various growth mechanisms and their unique features have promise as material design tools for diverse potential applications. This paper presents a straightforward method for metal–organic coordination-based mesocrystals using nickel ions and terephthalic acid. The coordinative compound between Ni2+ and terephthalic acid drives the particle-mediated growth mechanism, resulting in the mesocrystal formation through a mesoscale assembly. Subsequent carbonization converts mesocrystals to multidirectional interconnected graphite nanospheres along the macroscopic framework while preserving the original structure of the Ni-terephthalic acid mesocrystal. Comprehensive investigations demonstrate that multi-oriented edge sites and high crystallinity with larger interlayer spacing facilitate lithium ion transport and continuous intercalation. The resulting graphitic superparticle electrodes show superior rate capability (128.6 mAh g− 1 at 5 A g− 1) and stable cycle stability (0.052% of capacity decay per cycle), certifying it as an advanced anode material for lithium-ion batteries.

In this study, we report significant improvements in lithium-ion battery anodes cost and performance, by fabricating nano porous silicon (Si) particles from Si wafer sludge using the metal-assisted chemical etching (MACE) process. To solve the problem of volume expansion of Si during alloying/de-alloying with lithium ions, a layer was formed through nitric acid treatment, and Ag particles were removed at the same time. This layer acts as a core-shell structure that suppresses Si volume expansion. Additionally, the specific surface area of Si increased by controlling the etching time, which corresponds to the volume expansion of Si, showing a synergistic effect with the core-shell. This development not only contributes to the development of high-capacity anode materials, but also highlights the possibility of reducing manufacturing costs by utilizing waste Si wafer sludge. In addition, this method enhances the capacity retention rate of lithium-ion batteries by up to 38 %, marking a significant step forward in performance improvements.

Because plastics are cheap and light, their use is indispensable in our daily lives. However, the extensive use of plastics causes the disposal issue. Among various disposal processes, plastic recycling is of great attention because of minimizing waste and harmful byproducts. Herein, we recycle the most popular thermoplastic materials, high-density and low-density polyethylene, producing the anode materials for the Li-ion batteries. The electrochemical properties of the as-recycled soft carbon are investigated to study the energy storage capability as the anode of Li-ion batteries. Our work demonstrates the soft carbon recycled from plastic wastes is a promising anode material.