도핑 엔지니어링은 넓은 밴드갭, 낮은 전하 운반체 농도, 제한된 전하 수송 속도 등 리튬 이온 배터리용 산화물 기반 세라믹 분리막의 고유한 한계를 극복하는 효과적인 전략으로 부상했다. 이종 원자가 도핑은 전자 구조와 결함 화학을 변화시켜 산소 결함 및 결함 상태를 생성함으로써 리튬 이온 수송을 향상시키고 계면 저항을 감소시킨다. 또한, 도핑으로 인 한 격자 안정화는 기계적 강도를 개선하고 덴드라이트 침투를 억제하며 전기화학적 신뢰성을 향상시킨다. 산화물 기반 세라 믹 분리막은 고온에서 심각한 수축 및 용융 현상을 보이는 기존 폴리올레핀 분리막에 비해 우수한 열 안정성을 나타낸다. 기 계적으로 견고한 세라믹 골격은 열 응력 하에서도 구조적 안정성을 유지하고 내부 단락을 방지하여 배터리 안전성을 크게 향 상시킨다. 특히, 전하 운반체 활성화와 구조적 안정성이 균형을 이루는 최적의 도핑 농도 범위가 존재하여 전하 수송 성능과 안전성을 극대화할 수 있다. 종합적으로, 도핑 엔지니어링은 차세대 리튬 이온 배터리용 고성능 및 본질적으로 안전한 세라믹 분리막 개발을 위한 합리적인 전략을 제공한다.

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.

Bimetallic sulfides, as high-performance anode materials, exhibit high theoretical capacity. However, their practical application is hindered by inherent limitations, such as low electrical conductivity, sluggish charge transfer kinetics, and severe volume expansion. Interface-engineered heterostructures have emerged as a universal strategy to synergistically enhance conductive networks and suppress mechanical degradation. Carbon-based composites serve as optimal substrates due to their high conductivity and structural flexibility. In this study, we leverage the hierarchical porous architecture of expanded graphite (EG) to confine the self-assembly of Zn/Co precursors via a thiourea-assisted hydrothermal method, enabling in situ growth of Zn0.76Co0.24S nanoparticles within EG interlayers. Interfacial S–C covalent bonding, induced by π–π conjugation, establishes robust nanoscale coupling between Zn0.76Co0.24S and the carbon framework. The resulting “sandwich” heterostructure demonstrates exceptional cyclability (1086.9 mAh·g−1 after 500 cycles at 1.0 A·g−1) and rate capability (541.7 mAh·g−1 at 2.0 A·g−1). This work provides a generalizable design paradigm for high-performance multimetallic sulfide anodes through atomic-scale interface engineering.

국제해사기구(IMO)의 탈탄소 정책과 함께 소형선박 분야에서는 배터리 기반 전기추진의 도입이 확대되고 있다. 그러나 리튬이 온 배터리는 열폭주와 화재, 폭발 등 안전상의 위험을 내포하고 있어 이에 대한 체계적인 대응 방안이 필요하다. 본 연구는 한국, 노르웨 이 및 유럽의 관련 규정을 비교·분석하고, 이를 소형어선의 실제 적용 가능성 측면에서 검토하였다. 규정 분석을 통해 공통적으로 배터리 실에 대한 화재 탐지와 고정식 소화설비의 필요성이 확인되었으며, 소형선박을 대상으로 한 사례 검토에서는 가스계 소화설비는 설치 가 능성이 높은 반면, 수계 소화설비는 공간적·운항적 제약으로 적용이 어려운 것으로 나타났다. 따라서 연안 소형선박에서의 안전한 배터리 운용을 위해서는 해수에 의한 소화를 연구하거나 가스계 소화설비를 통한 대피시간 확보 및 육상 연계 등을 통한 안전 확보가 필요할 것 으로 확인되었다. 본 연구는 소형선박 배터리 안전설비의 현황과 적용성에 대한 기초 자료를 제공하며, 향후 전기추진 소형선박의 보급을 위한 설계 기준 및 안전 가이드라인 마련에 기여할 수 있을 것으로 기대된다.

To optimize the electrochemical properties of Ni-rich cathode materials, CPAN@SC-NCM811 is prepared via surface modification of single-crystalline LiNi0.8Co0.1Mn0.1O2 cathode material by adding 1, 2 and 3 wt.% of polyacrylonitrile, respectively. Significantly, the results obtained from X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) verify the successful synthesis of CPAN@SC-NCM811 cathode, which exhibits better electrochemical properties compared to SC-NMC811. After thorough milling and calcination of 2 wt.% polyacrylonitrile with SC-NCM811, the initial discharge specific capacity of prepared S2 sample is 197.7 mAh g− 1 and the capacity retention reached 89.2% after 100 cycles at a rate of 1.0 C. Furthermore, the S2 sample exhibits superior rate performance compared to the other three samples, in which these superior electrochemical properties are largely attributed to the optimal ratio of conductive cyclized polyacrylonitrile coatings. Overall, this work offers guidelines for modifying the surface of SC-NCM811 cathode materials for lithium-ion batteries with exceptional cycling and rate performance.

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 introduces a cost-effective electrochemical exfoliation technique for producing highly crystalline graphene from graphite. By optimizing key exfoliation parameters, including voltage, electrolyte concentration, and temperature, the efficiency of the exfoliation process and the quality of the resulting graphene were significantly improved. To further enhance crystallinity, minimize defect sites, and achieve superior material properties, the as-prepared electrochemically exfoliated graphene (AeEG) underwent post-heat treatment at temperatures ranging from 1500 to 2950 °C. When employed as a conductive additive, eEGs heat-treated at 1800 °C or higher significantly improved both cycle stability and rate performance in LIB coin cells, while maintaining a discharge capacity approximately 10–12 mAh/g higher than that of the control, which utilized Super P. The enhanced performance is attributed to the formation of an efficient conductive network and superior electron transport properties, driven by the high crystallinity and large aspect ratios of the heat-treated eEGs. These findings highlight the potential of eEG as a highly effective conductive additive for advanced battery industries, offering significant improvements in energy storage performance, specific capacity, and rate characteristics.

This study proposes a weighted ensemble deep learning framework for accurately predicting the State of Health (SOH) of lithium-ion batteries. Three distinct model architectures—CNN-LSTM, Transformer-LSTM, and CEEMDAN-BiGRU—are combined using a normalized inverse RMSE-based weighting scheme to enhance predictive performance. Unlike conventional approaches using fixed hyperparameter settings, this study employs Bayesian Optimization via Optuna to automatically tune key hyperparameters such as time steps (range: 10-35) and hidden units (range: 32-128). To ensure robustness and reproducibility, ten independent runs were conducted with different random seeds. Experimental evaluations were performed using the NASA Ames B0047 cell discharge dataset. The ensemble model achieved an average RMSE of 0.01381 with a standard deviation of ±0.00190, outperforming the best single model (CEEMDAN-BiGRU, average RMSE: 0.01487) in both accuracy and stability. Additionally, the ensemble's average inference time of 3.83 seconds demonstrates its practical feasibility for real-time Battery Management System (BMS) integration. The proposed framework effectively leverages complementary model characteristics and automated optimization strategies to provide accurate and stable SOH predictions for lithium-ion batteries.

Oxyfluorination treatment was used to enhance the electrochemical properties of SiOx/C-based lithium-ion battery anode materials by improving the dispersibility of multi-walled carbon nanotubes, which are conductive materials. The dispersibility, chemical, and morphological characteristics of the oxyfluorinated carbon nanotubes were confirmed through various analyses. In addition, the effect of oxyfluorination was analyzed by a lithium-ion battery performance test, and the discharge capacity and cycling stability were significantly improved. The introduction of oxygen functional groups onto the surface of the carbon nanotubes improved their dispersibility. The fluorine functional groups also acted as catalysts for the introduction of these oxygen functional groups onto the surface and improved the cycling stability by forming a LiF-based solid electrolyte interphase layer. The high discharge capacity and improved cycling stability of these lithium-ion batteries were attributed to the enhanced dispersibility of carbon nanotubes induced by oxyfluorination and the resulting enhancement of the 3D network in the anode material promoting the movement of lithium ions and electrons.

Iron selenides with high capacity and excellent chemical properties have been considered as outstanding anodes for alkali metal-ion batteries. However, its further development is hindered by sluggish kinetics and fading capacity caused by volume expansion. Herein, a series of FeSe2 nanoparticles (NPs)-encapsulated carbon composites were successfully synthesized by tailoring the amount of Fe species through facile plasma engineering and followed by a simple selenization transformation process. Such a stable structure can effectively mitigate volume changes and accelerate kinetics, leading to excellent electrochemical performance. The optimized electrode ( FeSe2@C2) exhibits outstanding reversible capacity of 853.1 mAh g− 1 after 150 cycles and exceptional rate capacity of 444.9 mAh g− 1 at 5.0 A g− 1 for Li+ storage. In Na+ batteries, it possesses a relatively high capacity of 433.7 mAh g− 1 at 0.1 A g− 1 as well as good cycle stability. The plasma-engineered FeSe2@ C2 composite, which profits from synergistic effect of small FeSe2 NPs and carbon framework with large specific surface area, exhibits remarkable ions/electrons transportation abilities during various kinetic analyses and unveils the energy storage mechanism dominated by surface-mediated capacitive behavior. This novel cost-efficient synthesis strategy might offer valuable guidance for developing transition metal-based composites towards energy storage materials.

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.

In this study, ester co-solvents and fluoroethylene carbonate (FEC) were used as low-temperature electrolyte additives to improve the formation of the solid electrolyte interface (SEI) on graphite anodes in lithium-ion batteries (LIBs). Four ester co-solvents, namely methyl acetate (MA), ethyl acetate, methyl propionate, and ethyl propionate, were mixed with 1.0 M LiPF6 ethylene carbonate:diethyl carbonate:dimethyl carbonate (1:1:1 by vol%) as the base electrolyte (BE). Different concentrations were used to compare the electrochemical performance of the LiCoO2/ graphite full cells. Among various ester co-solvents, the cell employing BE mixed with 30 vol% MA (BE/MA30) achieved the highest discharge capacity at − 20 °C. In contrast, mixing esters with low-molecular-weight degraded the cell performance owing to the unstable SEI formation on the graphite anodes. Therefore, FEC was added to BE/MA30 (BE/MA30-FEC5) to form a stable SEI layer on the graphite anode surface. The LiCoO2/ graphite cell using BE/MA30-FEC5 exhibited an excellent capacity of 127.3 mAh g− 1 at − 20 °C with a capacity retention of 80.6% after 100 cycles owing to the synergistic effect of MA and formation of a stable and uniform inorganic SEI layer by FEC decomposition reaction. The low-temperature electrolyte designed in this study may provide new guidelines for resolving low-temperature issues related to LIBs, graphite anodes, and SEI layers.

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.

Silicon-based anode materials have attracted significant interest because of their advantages, including high theoretical specific capacity (~4,200 mAh/g), low working potential (0.4 V vs Li/Li+), and abundant sources. However, their significant initial capacity loss and large volume changes during cycling impede the application of silicon-based anodes in lithium-ion batteries. In this work, we propose a silicon oxide (SiOx) anode material for lithium-ion batteries produced with a magnesio-thermic reduction (MTR) process adopting Boryeong mud as a starting material. Boryeong mud contains various minerals such as clinochlore [(Mg,Fe)6(Si,Al)4O10(OH)8], anorthite (CaAl2Si2O8), illite [K0.7Al2(Si,Al)4O10(OH)2], and quartz (SiO2). The MTR process with Boryeong mud generates a mixture of amorphous silicon oxides (SiOx and SiO2), and magnesium aluminate which helps to alleviate the volume expansion of the electrode during charge/discharge. To observe the effects of these oxides, we conducted various analyses including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-Transformation infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and cyclic voltammetry (CV) galvanic cell testing. The amorphous SiO2 and MgAl2O4 suppressed the volume expansion of the silicon-based anode, and excellent cycle performance was achieved as a result.

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.

This study prepares highly porous carbon (c-fPI) for lithium-ion battery anode that starts from the synthesis of fluorinated polyimide (fPI) via a step polymerization, followed by carbonization. During the carbonization of fPI, the decomposition of fPI releases gases which are particularly from fluorine-containing moiety (–CF3) of fPI, creating well-defined microporous structure with small graphitic regions and a high specific surface area of 934.35 m2 g− 1. In particular, the graphitic region of c-fPI enables lithiation–delithiation processes and the high surface area can accommodate charges at electrolyte/electrode interface during charge–discharge, both of which contribute electrochemical performances. As a result, c-fPI shows high specific capacity of 248 mAh g− 1 at 25 mA g− 1, good rate-retention performance, and considerable cycle stability for at least 300 charge–discharge cycles. The concept of using a polymeric precursor (fPI), capable of forming considerable pores during carbonization is suitable for the use in various applications, particularly in energy storage systems, advancing materials science and energy technologies.

Disposable masks manufactured in response to the COVID-19 pandemic have caused environmental problems due to improper disposal methods such as landfilling or incineration. To mitigate environmental pollution, we suggest a new process for recycling these disposable masks for ultimate application as a conductive material in lithium-ion batteries (LIBs). In our work, the masks were chemically processed via amine functionalization and sulfonation, followed by carbonization in a tube furnace in the Ar atmosphere. The residual weight percentages, as evaluated by thermogravimetric analysis (TGA), of the chemically modified masks were 30.6% (600 °C, C-600), 24.5% (750 °C, C-750), and 24.1% (900 °C, C-900), respectively, thereby demonstrating the possibility of using our proposed method to recycle masks intended for disposal. The electrochemical performance of the fabricated carbonized materials was assessed by fabricating silicon/graphite (20:80) anodes incorporating these materials as additives for use in LIBs. Using a coin-type half-cell system, cells with the aforementioned carbonized materials exhibited initial capacities of 553 mAh/g, 607 mAh/g, and 571 mAh/g, respectively, which are comparable to those of commercial Super P (591 mAh/g). Cell cycled at the rate of 0.33 C with C-600, C-750, and C-900 as additives demonstrated capacity retention of 53.2%, 47.4%, and 51.1%, respectively, compared with that of Super P (48.3%). In addition, when cycled at rates from 0.2 to 5 C, the cells with anodes containing the respective additives exhibited rate capabilities similar to those of Super P. These results might be attributable to the unique surface properties and morphologies of the carbonized materials derived from the new recycling procedure, such as the size and number of heteroatoms on the surface.

Highly safe lithium-ion batteries (LIBs) are required for large-scale applications such as electrical vehicles and energy storage systems. A highly stable cathode is essential for the development of safe LIBs. LiFePO4 is one of the most stable cathodes because of its stable structure and strong bonding between P and O. However, it has a lower energy density than lithium transition metal oxides. To investigate the high energy density of phosphate materials, vanadium phosphates were investigated. Vanadium enables multiple redox reactions as well as high redox potentials. LiVPO4O has two redox reactions (V5+/V4+/V3+) but low electrochemical activity. In this study, LiVPO4O is doped with fluorine to improve its electrochemical activity and increase its operational redox potential. With increasing fluorine content in LiVPO4O1-xFx, the local vanadium structure changed as the vanadium oxidation state changed. In addition, the operating potential increased with increasing fluorine content. Thus, it was confirmed that fluorine doping leads to a strong inductive effect and high operating voltage, which helps improve the energy density of the cathode materials.