bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Engineering Pore Structure of Hard Carbon Anode Materials for High-Power Potassium-Ion Hybrid Capacitors
Authors: Hwang Jongkook 
Published: December 2024

Potassium ion hybrid supercapacitors (PIHCs) have received great attention because of the low redox potential of K/K+ as well as the wide availability and low cost of potassium resources. However, the development of high power PIHCs has been largely limited by the sluggish K+ storage kinetics in battery-type carbon anode materials. Among the various strategies to improve the electrochemical performance of carbon anodes, pore structure engineering has been emphasized as an effective solution. Although several previous studies have reported the relationship between pore structure and K+ storage behavior, there is no consensus on the exact role of pores of different sizes. This is due to (i) the difficulties in preparing suitable model carbon materials with controlled porestructures, and (ii) the limited understanding of the role of pore structure in capacitive-controlled and diffusion-controlled K+ storage, respectively.
In this presentation, I will showcase the latest advancements from our research group in understanding the influence of pore structures on the K+ storage behaviors of hard carbon anode materials. We have developed carbon materials with controlled pore sizes (namely, micropore-dominated, ultramicropore/mesopore-mixed, and mesopore-dominated), and revealed a notable positive correlation between ultramicropore volume and enhanced capacitive K+ capacity. Additionally, our research team has successfully synthesized mesoporous carbon spheres with controlled mesopore openings. We found that prominently exposed mesopores significantly enhance the capacitive K+ storage capacity. This enhanced capacitive contribution in turn contributes to increased power densities in PIHC devices. These insights are pivotal in guiding the strategic design of pore structures to maximize capacitive K+ storage in carbon anode materials, thus propelling the development of high-power PIHCs.
Solvent-Confined Van Der Waals Gap Engineering to Improve Energy Storage in a 2D Layered Supercapacitor
Authors: Shim Jaehyung , Lee Chul-Ho 
Published: December 2024

Despite the rapidly growing demand for high-performance and eco-friendly supercapacitors in the pursuit of sustainable energy storage, achieving both high volumetric energy density and ultrafast charging remains a significant challenge. Two-dimensional layered materials (2DLM) have emerged as promising electrode materials due to their ability to form highly networked nanochannels. Understanding the transport behavior of ions within these nanochannels is crucial for efficient energy storage. Recent advancements have shown promise in creating nanochannels that enhance ion transport and storage. However, controlling the properties of nanochannels has been challenging due to their nanoscale size and limited choice of solvents primarily water.
Here, we propose a manufacturing method of 2DLM films that confines various solvents within the van der Waals gap, allowing for adjustable thickness from nano to micro dimensions. The confined solvents serve as nanofluidic channels, improving ion transport and achieving high-density energy storage. Our ethanol-confined films demonstrate a gravimetric capacitance of 302 F g-1 and a volumetric capacitance of 1033 F cm-3, measured at a scan rate of 100 mV s-1, which is twice as high as water-confined films. By selectively controlling the nanochannels, we can regulate the channel distance and density of the film, effectively enhancing the electrode surface potential and enabling ultrafast ion transport. This demonstration offers valuable insights into the design of 2DLM films for energy storage and conversion applications.
Anomaly Detection in Battery Charge-Discharge Experiments Using Multi-Task Auto-Encoder
Authors: Han Sangheon , Jung JinYoung , Han Skill , Kim Kyeongtaek 
Published: December 2024

Battery charge-discharge experiments require a long time for data collection, often taking several months. It is impossible to stop the experiment immediately when anomalous data is generated, such as rapid capacity fade in batteries, leading to inefficient waste of time.
To effectively continue the experiment, it's important to monitor the battery charge and discharge process in real time to anomaly behavior early.
Recently, research has been actively conducted to predict the characteristics and lifetime of batteries using deep learning. However, this deep learning approach necessarily requires a large amount of reproducible learning data. The fact that battery data is highly affected by changes in experimental conditions such as C-rate and temperature.
In this paper, we propose an anomaly detection algorithm model applicable to various experimental conditions by using multiple Auto-encoders (AE). We define this model as Multi-task Auto-encoder (MTAE), where each AE model is trained on normal battery operation data collected under different C-rate conditions.
MTAE reconstructs raw data measured at each cycle during charge-discharge experiments based on the learned normal data and calculates the reconstruction error. Using the reconstruction error values, we establish the 'reconstruction error distribution' for normal battery operation data, and based on this, set a threshold for detecting anomaly data. If the reconstruction error exceeds the threshold, it's identified as anomaly data.
Real-time anomaly detection using raw data through MTAE showed higher performance compared to AE models trained solely on a single C-rate, as evaluated by the Area Under the Curve (AUC). Although this paper categorized data based only on C-rate, future research will extend to include various characteristics such as temperature and pressure.
Rechargeable Aqueous Sodium-Ion Batteries with Iron/Titanium-Based Oxides As Negative Electrode Materials
Authors: Hirakuni Nozomi , Ugata Yosuke , Yabuuchi Naoaki 
Published: December 2024

Sodium-ion batteries with earth abundant elements have attracted much attention as an alternative to lithium-ion batteries in terms of their cost and abundant resources. In addition, aqueous sodium-ion batteries are expected to reduce the cost of battery manufacturing cost and solve safety issues. In this study, O3-type metastable Na0.5Fe0.5Ti0.5O2 oxide is synthesized, and their electrode performances as negative electrode materials for aqueous sodium-ion batteries are examined.
Metastable Na0.5Fe0.5Ti0.5O2 with cation vanact sites was synthesized by the chemical oxidation of NaFe0.5Ti0.5O2. Figure 1 shows the XRD patterns of Na
x
Fe0.5Ti0.5O2 before and after soaking into water. From diffraction lines, the crystal structure of both samples can be assigned as an O3-type layered structure. The weakend peak intensity of the 003 diffraction line and the shrinkage of c-axis value after soaking into water indicates the partial extraction of Na ions and the successful formation of Na0.5Fe0.5Ti0.5O2. This fact is further supported by oxidation of Fe after soaking into water by X-ray absorption spectroscopy (Fig. 2). Galvanostatic charge/discharge curves of the samples before and after soaking into water are shown in Fig. 3. The sample after soaking delivers a larger initial charge (reduction) capacity because of the Fe oxidation and enriched vacant sites in the host structure.
Based on these results, the electrochemical properties of Na0.5Fe0.5Ti0.5O2 and its potential application to aqueous sodium ion batteries will be discussed in detail.

Figure 1
Study on High-Voltage Cathode Li-Ni-Mn Spinel Oxides with Low-Temperature Magnetism
Authors: Ishimori Yuki , Sakurai Hiroya , Takada Kazunori , Nakamura Tatsuya 
Published: December 2024

Lithium-ion rechargeable batteries have been attracting researcher’s interest, because they are candidate to address environmental issues, especially for application to electric vehicles and stationary energy storage systems. The battery operating voltage is one of the factor affecting the energy density of battery cell, and therefore positive electrode with high operating voltage is very attracting. A typical high-voltage cathode material, LiNi0.5Mn1.5O4 is an end member of LiNixMn2-xO4 solid solution compounds (0.00<x<0.50). From the previous study, it is known that LiNi0.5Mn1.5O4 spinel is a ferri-magnetic material with large magnetic moment and high transition temperature. In this work, the compounds of LiNixMn2-xO4 (0.40<x<0.50) are studied with both low-temperature magnetism and electrochemical charge-discharging. Additionally, the correlation between electrochemical and magnetic properties is also discussed.
LiNixMn2-xO4 (0.40<x<0.50) were prepared by gelation of nitrate/citrate solution, thermal decomposition at 500 ℃ and annealing under various conditions (temperature and atmosphere). Under the preparation condition at relatively low temperature (700 ℃) in oxygen atmosphere, they were single phase of cubic spinel with fine particles. The lattice parameters monotonously decreased, as x increased. The charge-discharge profiles have twin plateaus around 4.7 V, to Ni2+/Ni3+ and Ni3+/Ni4+ redox signals, with a small signal at ~4.0 V. The capacity at >4.5 V formers increased with x and that at <4.5 V was reduced. From the magnetic evaluation, the saturation magnetization at 2 K (Ms) increased with x, and simultaneously, the ferri-magnetic/paramagnetic transition temperature (Tc), evaluated from temperature dependence of the saturation magnetization, shifted higher. These results exhibited the following relation-ships (presented in Fig. 1); the capacity at >4.5 V was almost proportional to Ms, and the operating voltage was proportional to Tc. However, it was found that the magnetic response under weak magnetic field was not usual (shown in Fig. 2) and it implied two-step phase transition around Tc. The anomaly was thought to be attributed to magnetic in-homogeneity, which is very sensitive to the specimen characters. The analysis of experimental results of specimens prepared under different conditions are being carried out and then presented and discussed at the conference.

Figure 1
Multi-Dopant Influence on the Volume Changes of Layered-Oxide Cathodes for Lithium-Ion Batteries
Authors: Miyazaki Tatsuya , Minamida Atsusa , Kawai Kosuke , Kubota Kei , Okubo Masashi 
Published: December 2024

The growing global market of electric vehicles demands performance improvement of lithium-ion batteries (LIBs). Layered transition-metal oxide (LiMO2) is widely used as cathode materials for LIBs owing to its large energy densities. However, LiMO2 exhibits a large volume change upon (de)lithiation, which induces a mechanical stress inside a particle.1 Consequently, interparticle cracking occurs with repeating charge/discharge cycles, resulting in severe performance degradation. Introducing redox-inactive cations within and between transition-metal layers has been widely employed to suppress such volume changes. For example, Zhang et al. proposed that doping Ti, Mg, Mo, and Nb into LiMO2 could improve the cycle performance by reducing the volume change upon charge/discharge.2,3 In this study, the roles of multiple dopants in suppressing volume changes of LiNi0.5Mn0.5O2 are investigated using operando X-ray diffraction measurements.
LiNi0.5Mn0.5O2 and four multi-doped samples (LiNi0.5Mn0.43Ti
x
Mg
y
Mo
z
Nb0.07–x–y–z
O2) were synthesized by the co-precipitation methods. Working electrodes were prepared by coating an Al current collector with a slurry of active material, acetylene black, and polyvinylidene fluoride at a weight ratio of 80:10:10. 2032-type coin cells were fabricated using the working electrode, Li metal as a counter electrode, and 1 mol L–1 LiPF6 ethylene carbonate/diethyl carbonate (1:1 v/v%) + 2 wt% vinylene carbonate as an electrolyte. Galvanostatic charge/discharge measurements were performed at a C-rate of 0.1C (28 mA g–1). Laminated cells with the LiMO2 electrodes and 1 mol L–1 LiPF6 ethylene carbonate/diethyl carbonate (1:1 v/v%) electrolyte were fabricated for operando X-ray diffraction measurements with a transmission mode.
Powder X-ray diffraction measurements confirm the successful synthesis of all LiMO2. Galvanostatic charge/discharge measurements show that LiNi0.5Mn0.5O2 (non doped), LiNi0.5Mn0.43Ti0.03Mg0.02Mo0.02Nb0.01O2 (4-element doped), LiNi0.5Mn0.43Ti0.03Mg0.02Mo0.02O2 (3-element doped (w/o Nb)) deliver larger reversible capacities (~190 mAh g–1) than LiNi0.5Mn0.43Mg0.02Mo0.02Nb0.01O2 (3-element doped (w/o Ti)) and LiNi0.5Mn0.43Ti0.01Mg0.02Nb0.04O2 (3-element doped (w/o Mo)). After the 70th cycle, non-doped LiNi0.5Mn0.5O2 exhibits greater capacity retention (90%) than four-element doped and three-element doped (w/o Nb) LiNi0.5Mn0.5O2 (86% and 85%, respectively). Operando X-ray diffraction measurements show that the volume change (ΔV/V) at 80% depth of charge was −4.2%, −1.8%, and –3.3% for no-doped, four-element doped, and three-element doped (w/o Nb) LiMO2. These results indicate that a Nb dopant plays an important role in the suppression of a volume change during the first charge.

Yan, P., et al., Nat Commun.
8, 14101 (2017).

Zhang, R., et al., Nature
610, 67–73 (2022).

Zhang, R. et al., Energy.
8, 695–702 (2023).

Figure 1
Theoretical Analysis of Anion Intercalation Process into Cathode Conductive Carbon
Authors: Nakamura Kou , Takenaka Norio , Hagiwara Satoshi , Otani Minoru , Yamada Atsuo 
Published: December 2024

High-voltage Li-ion batteries have been extensively studied to increase the energy density of batteries. To achieve this goal, 5 V class cathode materials have been developed, but the long-term stable operation has not been achieved. Recently, we reported that the poor cycle stability comes not only from the oxidative degradation of the electrolyte and/or cathode active material, but also from side reactions caused by the insertion of anions into the interlayer of a cathode conductive carbon [1]. However, the detailed mechanism of anion insertion into the conductive carbon is still not well understood. In this study, we theoretically investigated the anion insertion process at the interface between a graphite and EC-based electrolyte solution (1 M LiPF6 / EC).
We adopted a density functional theory (DFT) in combination with the effective screening medium and reference interaction site model (ESM-RISM) method to analyze the insertion process of a PF6
- anion into the graphite [2]. The simulation cells are composed of graphite electrode (C252(PF6)9H36) and the 1 M LiPF6 / EC electrolyte, where the entire graphite electrode are treated quantum mechanically, whereas the electrolyte components are treated classically by the RISM method. The activation energy was calculated by computing the grand potential (Ω) at each point while moving a PF6
- anion from its initial position on the electrolyte side (r = 20 Å) to the electrode interior (r = 0 Å). These calculations were performed at two different electrode potentials, the potential of zero charge (PZC) and the equilibrium potential of the anion insertion reaction, respectively. All the DFT and ESM-RISM calculations were conducted using the Quantum Espresso v.6.1 code.
The figure shows the profiles of Ω along the insertion process of the PF6
– anion into the graphite layer. The activation energies were estimated to be 0.49 eV (ΩPZC, black line) and 0.37 eV (Ωeq, red line) at the PZC and the equilibrium potential, respectively, considerably smaller than that of Li+ (0.6 eV) [3]. Importantly, the coordination number of EC molecules around PF6
– (N
EC, blue line) decreases from about 10 Å and Ω becomes correspondingly unstable, indicating that the desolvation of PF6
– contributes significantly to the activation barrier. Furthermore, systematic calculations of the desolvation energies for different solvent species show that the calculated values tend to increase as the dipole moment of the solvent molecule decreases. Therefore, a use of solvents with smaller dipole moments would increase the desolvation energy, thus suppressing the anion insertion.
1) S. Ko et al., Joule, 5, 998 (2021).
2) S. Nishihara et al., Phys. Rev. B, 96, 115429 (2017).
3) J. Haruyama et al., J. Phys. Chem. C, 122, 9804 (2018).

Figure 1
Preparation and Characterization of LGVO/PEO Composite Electrolytes with Wet Process
Authors: Ozaki Taiyo , Nakamura Tatsuya , Kakibe Takeshi 
Published: December 2024

All-solid-state lithium-ion batteries (ASSLBs) have become a good candidate for energy storage devices with safety and long-life time. It is essential to apply an appropriate solid electrolyte, because it is quite important to build the electrode/electrolyte interface with good chemical, electrochemical and mechanical properties [1, 2]. The previous studies reported that LISICON compound Li3.5Ge0.5V0.5O4 (LGVO) solid electrolyte has good compatibility with layered rock salt cathode oxides [3]. However, the LGVO solid electrolyte phase is easily reductive-decomposed in contact with lithium metal anode. In order to avoid direct contact between LGVO electrolyte and Li metal anode, it is useful to construct intermediate polymer electrolyte layer with high Li+ ionic conductivity between them. In this paper, the preparation conditions of polyethylene oxide based polymer electrolyte (PEO-based SPE) film by wet method were discussed. In addition, the polymer film was prepared on the LGVO solid electrolyte layer, and the LGVO/PEO interfacial properties were also studied.
PEO-based SPE slurry was prepared by dissolving PEO and different concentrations of Lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) with/without Al2O3 nanoparticle in acetonitrile. PEO-based SPE slurry was uniformly coated on the LGVO membrane and dried in a vacuum to obtain LGVO/PEO laminated electrolytes.
X-ray diffraction patterns of the several PEO-based SPE are shown in Fig. 1. Low Li+ concentrated PEO-based SPE (with Li+ : EO ratio = 1:20) exhibited typical PEO diffraction peaks at 15°, 19° and 23°. On the other hand, the crystallinity degree of PEO in high Li+ concentrated PEO-based SPE (with Li+ : EO ratio = 1:10) decreased dramatically. Especially, there are no diffraction peaks in high Li+ concentrated PEO-based SPE (with Li+ : EO ratio 1:10) with Al2O3 nanoparticle addition. Fig. 2 shows temperature dependence on the ionic conductivities of the PEO-based SPE (with Li+ : EO ratio 1:10) with Al2O3 nanoparticle in temperature range from 10 to 80 °C. The ionic conductivity of the PEO-based SPE showed a sufficiently higher ionic conductivity (4.25 × 10-3 Scm-1) at 60 °C.
This study was supported in part by the JST GteX (grant number JPMJGX23S2).
[1] E. Quartarone, P. Mustarelli, “Electrolytes for solid-state lithium rechargeable batteries: recent advances and perspectives”, Chem. Soc. Rev., 40, 2525-2540, (2011).
[2] R. Chen, Q. Li, X. Yu, L. Chen, H. Li, “Approaching Practically Accessible Solid-State Batteries: Stability Issues Related to Solid Electrolytes and Interfaces”, Chem. Rev., 120, 6820-6877 (2020).
[3] T. Okumura, T. Takeuchi, H. Kobayashi, “All-Solid-State Batteries with LiCoO2-type electrodes: realization of an impurity free interface by utilizing a co-sinterable Li3.5Ge0.5V0.5O4 electrolyte”, Appl. Energy Mater. 4, 30-34 (2021).

Figure 1
Study on the Structural and Electrochemical Characteristics of End of Life Battery Electrode Delaminating Process
Authors: Kim Byeoungseok , Jin Sungjin , Park Sangho 
Published: December 2024

Demand for lithium-ion batteries (LIBs) has been increased dramatically over the years due to the rapid market expansion of electric vehicles and Energy storage system(ESS). Current commercial lithium ion batteries mainly contain nickel, cobalt, manganese metal oxides, lithium, phosphates, aluminum, copper, graphite, organic electrolytes and other chemicals. Therefore, the recycling and reuse of used lithium-ion batteries at the end of their useful life are of great interest by many researchers. However, due to the high energy density, high safety and low price of lithium-ion batteries, the difference and variety are large, which poses great difficulties in recycling waste lithium-ion batteries.
Lithium ion batteries recycling typically involves both physical and chemical processes. Physical processes typically include pretreatment and direct recovery of electrode materials. These processes typically include decomposition, crushing, screening, magnetic separation, washing, heat treatment, etc. The chemical processes can generally be divided into pyrometallurgical and hydrometallurgical processes which include leaching, separation, extraction and chemical/electrochemical precipitation. Recently, recycling technologies for lithium secondary batteries through a direct regeneration process have been attracting attention. Directly regeneration technique has the advantages of short recovery route, low energy consumption, eco-friendly compared to pyrometallurgical and hydrometallurgical processes. In order to recover the cathode active material from the separated electrode plate, a process for separating the PVDF binder and the cathode active material is required. In general, N-methyl-2-pyrrolidone (NMP) is the most common solvent for the manufacture of cathode electrodes in the battery industry. Although ~99% of the solvent used in electrode manufacturing is recovered, it is however limited in several countries due to negative environmental impacts.
In this study, the cathode materials were separated electrode from used lithium ion cell using various wet-chemistry. Chemical, structural, and electrochemical characteristics of the cathode materials and substrate were investigated.
NMR Insights into Designing Safe and Efficient Lithium-Ion-Batteries with Solid Electrolyte
Authors: Shin Yoonju , Han Ji-Hoon , Kim Dokyung , Cho Young Whan , Ahn Sangdoo , Lee Young Joo 
Published: December 2024

The inherent risk of explosion in widely used lithium-ion-batteries has ignited greater interest in the development of more efficient and safer energy storage. Notably, there is growing attention on all-solid-state batteries for their ability of providing both safe and efficient energy storage. Among the promising candidates, we focused on argyrodite-type electrolytes exhibiting high ionic conductivity on the order of some mS/cm at room temperature.
In this study, we compared dual-substituted argyrodite-type electrolytes to observe the effect of the anion substitution on the physical properties of the solid electrolytes using solid state NMR. We investigated the correlation between anion substitution and the local dynamics of lithium ions through NMR relaxometry. We measured 7Li spin-lattice relaxation times (T1) in various temperature, fitted the T1 values into the Arrhenius equation and calculated the activation energy. Furthermore, by comparing the peak intensity of NMR 1D spectra before and after cycling, we confirmed the movement of Li ions between cathode and electrolyte.
In short, our findings, obtained via solid-state NMR, deepen our insights on electrolytes down to the atomic level. This work gained ground for future research to develop the efficient and safe energy storage systems and drive innovation in all-solid-state batteries.