In this study, we report the synthesis of nitrogen‐doped Mn 3 O 4 /amorphous carbon (N–Mn 3 O 4 /AC) composites via a one‐step solvothermal method, employing linoleic acid (LA) and N,N‐dimethylacetamide (DMAc) as dual‐functional agents for carbon templating and nitrogen doping, respectively. The presence of high‐valent manganese‐oxo (Mn─O) moieties (terminal Mn 4+ ═O), graphitic domains, and redox‐active nitrogen functional groups in the carbon matrix and onto the Mn 3 O 4 surface effectively enhanced the electrical conductivity and redox activity of the resulting composite. Electrochemical performance revealed that the N‐doped Mn 3 O 4 /AC delivered a high specific capacitance of 293.3 F g −1 at a current density of 0.5 A g −1 in 1 M Na 2 SO 4 electrolyte, while maintaining an excellent rate capability of 79% at 5 A g −1 . Remarkably, this N‐doped Mn 3 O 4 /AC electrode achieved 4.4 times higher capacitance than undoped Mn 3 O 4 . Moreover, the composite retained over 80% of its initial capacitance after 2000 charge–discharge cycles at 0.5 A g −1 , underscoring its excellent long‐term stability. Electrochemical impedance spectroscopy (EIS) revealed low charge transfer resistance and favorable ion diffusion kinetics. These findings establish N‐doped Mn 3 O 4 /AC composites as a promising and scalable electrode material for high‐performance supercapacitors and hybrid energy storage systems.

In this study, a binder-and conductive additive-free sulfur electrode was fabricated by electrochemically depositing solid sulfur onto a stainless-steel current collector. Prior to electrode fabrication, the growth process of sulfur as a function of deposition time (5, 15, 30, and 60 min) was systematically investigated. At the initial deposition stage, micro-sized particles with irregular shapes were gradually transformed into spherical ones at 30 min. After 60 min, only spherical sulfur particles with an average diameter of 5.2 mu m completely covered the surface of the current collector. The as-deposited sulfur electrode exhibited unstable discharge behavior due to weak adhesion to the current collector. In contrast, the application of a conductive carbonized PAN (CPAN) interlayer enabled smooth electrochemical reactions during discharge-charge cycling. To further improve cell performance, a glass fiber (GF) separator was employed in combination with CPAN, and its electrochemical properties were compared with those of a commercial PP separator. The GF-cell exhibited superior performance over the PP-cell, delivering higher discharge capacity (1120 vs. 993 mAh/g at 0.1C) and improved capacity retention (86.6% vs. 45.2% at 0.2C after 200 cycles).

Lithium-sulfur batteries (LSBs) have emerged as a promising candidate for high-energy-density storage due to their high theoretical specific capacity (similar to 2600 Wh/kg) and the low cost of sulfur. However, their practical application is limited by significant challenges, including the polysulfide shuttle effect, sluggish redox kinetics, and low sulfur utilization, all of which lead to rapid capacity degradation. To overcome these issues, interlayer engineering has been investigated as an effective strategy to improve electrochemical stability. In this study, a multi-metallic interlayer (Zn0.4Fe0.6Co2O4/carbon cloth (CC)) was synthesized via a hydrothermal method followed by annealing. ZnFeCo2O4 offers strong polysulfide affinity and catalytic activity, promoting both the immobilization and conversion of lithium polysulfides, while CC serves as a conductive matrix to enable efficient charge transport. The optimized LSBs deliver a high specific capacity (1330.2 mAh/g at 0.2C) with extended cycle life under lean electrolyte and high sulfur loading conditions, demonstrating the effectiveness of this multi-metallic interlayer design.

Mixed-valence MnO/Mn3O4/carbon (MnO/Mn3O4/C) composites were synthesized via a one-step solvothermal process followed by thermal annealing, utilizing N,N-dimethylacetamide (DMAc) as a dual-function solvent and insitu carbon source. By precisely tuning the annealing temperature, the structural and electrochemical properties of the resulting composites were optimized. Notably, the sample annealed at 500°C (Mn–N5) exhibited a balanced Mn2+/Mn3+ ratio, abundant oxygen vacancies, and a conductive sp2-rich carbon framework. These features collectively enhanced lithium-ion diffusion, electron transport, and mechanical integrity. As an anode material, Mn–N5 delivered a high reversible capacity of 861 mAh g⁻1 at 0.2 A g⁻1, retained 309 mAh g⁻1 at 2 A g⁻1, and maintained 473 mAh g⁻1 after 1000 cycles at 0.5 A g⁻1. Kinetic analysis and impedance spectroscopy confirmed improved charge t ransfer and pseudocapacitive behavior, d riven by the synergistic effects of the heterostructured MnOx and carbon network. These results demonstrate a scalable and cost-effective strategy for engineering high-performance Mn-based anodes suitable for next-generation lithium-ion batteries.

Most alloying-type anodes for Na-ion batteries are fundamentally limited in ultrafast-charging applications due to the formation of Zintl phases: intermetallic compounds with intrinsically high electrical resistivity. This work demonstrates how to overcome this fundamental limitation by employing metal sulfide-based conversion anodes (NiS, CuS, and MnS), which follow a distinct electrochemical pathway that avoids Zintl-phase formation. During cycling in ether-based electrolytes, these sulfides undergo conversion reactions that spontaneously generate highly conductive, in-situ formed metal nanoparticles embedded within a self-assembled three-dimensional nanoporous Na2S matrix. This unique composite structure forms a dual-function architecture that enables both efficient ion diffusion and long-range electron transport, even when using inexpensive microsized sulfide particles. Among the tested materials, NiS exhibits the best performance, delivering a reversible capacity of 600 mAh g-1 Density functional theory and machine-learning-based molecular dynamics simulations reveal that the strong Ni-S bonding in the intermediate phases suppresses nanoparticle coarsening, resulting in uniformly distributed, nanoscale Ni particles that form an efficient percolation network. These findings establish a new design paradigm for Zintl-free conversion anodes, offering a practical and scalable route toward high-performance, fast-charging Na-ion batteries. at 1C, exceptional cycling stability over 3800 cycles at 10C, and a high-rate capacity of 358 mAh g-1 at 30C.

The utilization of lithium-sulfur (Li-S) batteries is limited by their high volume expansion, low ionic conductivity, and the dissolution of lithium polysulfides in the sulfur electrode when conventional binders are used. This study introduces a cross-linked multifunctional binder designed to ensure strong contact with polysulfides and excellent mechanical properties through a polymerization process between polyvinyl alcohol (PVA) and succinimide (SUM). The abundant polar groups in PVA/SUM interact with polysulfides, reducing their mobility. The amide groups facilitate rapid ion transfer by interacting with Li-ions. Consequently, the sulfur electrode with the cross-linked PVA/SUM binder (PVA-10 wt% SUM) exhibits outstanding rate performance and impressive capacity retention of 616 mAh/g after 200 cycles at a 1.0C-rate, even with a sulfur loading over 4 mg/cm2. This work provides a cost-effective and efficient solution for water-soluble cross-linked binders in high-performance Li-S batteries, addressing the problem of polysulfide dissolution effectively.

The practical deployment of lithium-sulfur batteries (LSBs) is limited by the poor conductivity of sulfur and the diffusion of lithium polysulfides. To overcome these challenges, we present a multifunctional separator modified with silicon nitride (SiN) and high-surface-area porous carbon (PC, >2000 m(2)/g) coated on both sides of a polypropylene (PP) membrane. This dual-coated SiN-PC/SiN separator not only suppresses polysulfide shuttling but also enhances lithium-ion transport and catalytic conversion. The modified separator effectively stabilizes the lithium anode, reduces dendrite formation, and ensures uniform lithium plating/stripping. As a result, the LSBs demonstrate remarkable cycling stability with a specific capacity of similar to 600 mAh/g at 1.0C and a high sulfur loading (>3.5 mg/cm(2)) over 200 cycles. This design offers a promising strategy for improving both the cathode and anode interfaces, paving the way for high-performance LSBs.

Designing a material structure that supports high-capacity and long cycle life in silicon (Si) anodes has been a long-standing challenge for advancing lithium-ion batteries. Yolk-shell design has been considered a most promising design for alleviating the volume expansion feature of Si. However, the significant void between the Si core and the outer shell limits electrical contact and the complete utilization of the Si core and deteriorates the battery performance upon cycling. In this study, we synthesized a bridged multi-layered yolk-shell (MYS) structure design via thermal decomposition of SiH4 and carbon oxidation in the air atmosphere. This MYS design features a void space to accommodate the volume expansion of the Si core. It includes a carbon bridge (CB) that connects the Si core and outmost shell containing SiOx /Si/SiOx which improves the electrical contact and lithiation kinetics of the Si core and addresses fundamental issues of low contact between core and shell. As a result, the CB-MYS structure exhibits a high specific capacity of 2,802.2 mAh g-1, an initial Coulombic efficiency of 90.0%, and maintains structural integrity and stable cycling performance. Hence, we believe the CB-MYS structure is a promising engineering design to enhance the performance of high-capacity alloy anodes for next-generation lithium-ion batteries.

The crystal structures of orthosilicate cathode materials play a critical role in determining the physical and chemical properties of Li-ion batteries. Accurate predictions of these crystal structures are essential for estimating key properties of cathode materials in battery applications. In this study, we utilized crystal structure data from density functional theory (DFT) calculations, sourced from the Materials Project, to predict monoclinic and orthorhombic crystal systems in orthosilicate-based cathode-based materials with Li–Si–(Fe, Mn, Co)–O compositions. An artificial neural network (ANN) model with a 6-22-22-22-1 architecture was trained on 85% of the data and tested on the remaining 15%, achieving an impressive accuracy of 97.3%. The model demonstrated strong predictive capability, with only seven misclassifications from 267 datasets, highlighting its robustness and reliability in predicting the crystal structure of orthosilicate cathodes. To enhance interpretability and model reliability, we employed the Index of Relative Importance (IRI) to identify critical features influencing predictions. Additionally, a user-friendly graphical user interface was also developed to facilitate rapid predictions, enabling researchers to explore structural configurations efficiently and accelerating advancements in battery materials research.

Lithium/sulfur (Li/S) batteries are potential candidates for next-generation batteries owing to their high theoretical energy densities and low fabrication costs. High energy density in a practical Li/S cell can be realized using a high-loading sulfur cathode with a lean electrolyte. For commercialization, a high-loading sulfur electrode must have a stable cycling performance at a high rate. In this study, phosphorus and nitrogen codoped porous carbon was prepared and utilized as a sulfur host for a high loading sulfur electrode. The Li/S batteries exhibited stable cycling performance at 1 C. The Li/S batteries delivered a capacity of 553 mAh g-1 after 200 cycles at a 1 C rate with a sulfur cathode loading of 4 mg cm-2 and an electrolyte-to-sulfur ratio of 7 mL g-1, with a capacity degradation rate of only 0.068% per cycle. At a higher sulfur loading of 7 mg cm-2, the batteries exhibited an initial capacity of 1207 mAh g-1, which decreased to 736 mAh g-1 after 100 cycles at 0.1 C. This phosphorus and nitrogen codoped porous carbon appears as a promising sulfur host for high-loading sulfur electrodes in Li-S batteries, enabling stable cycling performance at a high rate under lean electrolyte conditions.

As next-generation energy storage technologies, lithium-sulfur (Li-S) batteries have garnered a lot of attention because of their inexpensive cost, high theoretical capacity, low energy density, and lack of toxicity. Nonetheless, significant challenges about the dissolution of lithium polysulfides and the low conductivity of sulfur still need to be addressed. In this study, a low-cost kenaf stem precursor was pyrolyzed in a single step using a sodium hydroxide activating agent to create a micro/mesoporous carbon (KPC), which is porous carbon derived from the stem of a kenaf tree. This allowed for the efficient encapsulation of sulfur. Through a melt-diffusion technique, sulfur was loaded into the synthesized KPC pores (sulfur-laden KPC; S@KPC). The S@KPC composite has a higher loading of sulfur content (68%) inside the micro/mesoporous carbon. Additionally, with a multifunctional polyvinylpyrrolidone (PVP) coating (with different ratios), the resultant composite displays higher electrochemical performance, including a high specific capacity (1228 mAh/g at 0.3 C-rate (PVP-coated S@KPC 1-4)) and a good cycling life with a reversible capacity of 632 mAh/g after 100 cycles at 0.3 C-rate. Both the protective coating and the micro/mesoporous structure of the carbon inhibit polysulfide dissolution while simultaneously increasing interfacial stability and simplifying the charge transport pathways. This tactical combination leads to a high reversible capacity, better cycle reversibility, and good rate capabilities in Li-S batteries.

Si and graphite composite (Si/G) anodes are considered promising alternatives to traditional graphite anodes, providing a higher specific capacity and improved cycle performance for high-energy Li-ion battery applications. However, the practical application of composite electrodes has been hindered by the large volume expansion of the inner Si-based particles, which leads to interfacial instability and electrode structure disintegration. This paper presents a novel solution: a cross-linked polyvinyl alcohol (PVA)/malonic acid (MA) binder for Si/G composite electrodes, synthesized through a straightforward cross-linking process. This water-soluble crosslinked polymer binder, which incorporated a carboxylic acid crosslinker (1wt.% MA and PVA (PM11)), demonstrated excellent adhesive and good elongation properties are significantly reduced the Si/G composite anode volume expansion compared with that of a commercial binder. The developed crosslinked polymer binder PM11 facilitated an 81.5% capacity retention after 200 cycles at 0.5 C-rate. These findings highlight the pivotal role of these novel carboxylic acid cross-linker binders (crosslinked polymer binders (PM11)) in the development of next-generation Li-storage devices, emphasizing the significant impact of this study on energy storage.

Sodium-ion batteries (SIBs) have attracted increasing attention as a cost-effective and sustainable alternative to lithium-ion batteries (LIBs) for large-scale energy storage owing to the abundance of sodium and its electrochemical similarity to lithium. However, the development of suitable anode materials remains a key challenge. Alloy-type metals are considered promising anode candidates because they offer high theoretical capacities and multiple electron transfer reactions. In this study, we investigate a Bi-Sn alloy foil anode prepared by rolling to a thickness of 36 μm and punching into 4 mm-diameter discs. The foil is employed directly as the anode without the addition of conducting agents or binders, enabling the intrinsic electrochemical behavior of the active material to be evaluated. Electrochemical tests were performed in Swagelok-type cells using sodium metal as the counter electrode and two different electrolytes: 1 M NaPF6 in 1,2-dimethoxyethane (DME) and 1 M NaPF6 in ethylene carbonate/diethyl carbonate (EC/DEC). The Bi-Sn foil demonstrates excellent cycling performance in DME, retaining a capacity of 530 mAh g-1 (14.84 mAh cm-2) after 100 cycles at 0.1 Cequivalent to 91.5% of its theoretical capacity. In contrast, rapid capacity fading is observed in EC/DEC, underscoring the critical role of electrolyte chemistry in alloy-type anodes. Morphological analyses reveal that during cycling in DME, the Bi-Sn foil undergoes significant mechanical deformation, including cracking and pulverization into nanoscale domains. However, the fragmented particles spontaneously reconstruct into a porous structurea phenomenon referred to as self-healing. This porous structure maintains electrical connectivity to the current collector, enabling capacity retention. These findings demonstrate that pulverization is not inherently detrimental to alloy-type anodes; rather, it can be mitigated by using an ether-type electrolyte to facilitate self-healing. This strategy offers a new pathway for the development of alloy-type anodes composed of low-melting-temperature metals, such as Bi, Sn, and Pb.

The lithium/sulfur redox couple is considered as the next-generation battery system owing to its high theoretical energy density and abundance of sulfur. Numerous efforts have been devoted to overcome the inherent issues such as low electronic conductivity of sulfur, dissolution of lithium polysulfides, volume change, and a lithium anode. A lot of properties have been improved for the last decades. However, commercialization is required additional challenges, i.e., decreasing electrolyte (low ratio of electrolyte to sulfur), robust sulfur electrode architectures, and lithium stability during cycling. This article encompasses the basic principle of lithium/sulfur batteries, the critical challenges of lithium/sulfur batteries, and the efforts made so far to conquer the issues. The recent advancement in the sulfur cathode, electrolyte, binder, and separator are summarized. The perspectives of lithium/sulfur batteries are also presented.

In lithium-ion batteries (LIBs), silicon (Si) is the most promising alternative anode material to graphite owing to its high theoretical capacity (4200 mAh/g), high energy density, low cost, and easy availability. However, the practical applications of Si-based anodes are restricted owing to their massive volume expansion (>300%), which leads to the pulverization of Si and fast capacity fading of the electrodes. The optimization of polymer binders has been considered an effective strategy for decreasing the volume expansion of Si electrodes during the charge/discharge process. In this study, a cross-linked poly(vinyl alcohol) (PVA)-malonic acid (MA) water-soluble polymeric binder was prepared through the polymerization of PVA and MA. The synthesized cross-linked PVA-MA composite binder with hydroxyl groups (OH) and ester bonds remarkably enhanced the mechanical and adhesion properties. A Si electrode with a composite binder containing PVA and 10 wt %MA exhibited a high initial capacity of 3558 mAh/g and maintained 2267 mAh/g after 100 cycles at a rate of 0.3 C compared to the traditional PVdF binder (2306 mAh/g at a rate of 0.3C). This study offers a method to fabricate stable Si electrodes using sustainable Si sources and eco-friendly carboxylic acid-based cross-linkers for synthesizing cross-linked polymer binders.

Piezoelectric sensors for underwater sonar require high hydrostatic piezoelectric properties (dh, gh and HFOM), and research is being conducted on various types of piezoelectric composites to improve them. In this study, research was conducted to improve the hydrostatic piezoelectric properties of 1-3 type piezoelectric composites using PZT piezoelectric ceramics and polymers. First, the appropriate material and volume fraction of the piezoelectric ceramic were selected through numerical analysis, and then experimental specimens were produced by applying various porosity of the polymer matrix. As a result of the experiment, it was confirmed that dh increased by 75% as the porosity of the polymer matrix increased. This phenomenon was analyzed to be caused by a change in elastic modulus. In addition, gh and HFOM also increased by 70% and 210% as the porosity of the polymer matrix increased. These results experimentally demonstrated that controlling the porosity of the polymer matrix is useful for improving the hydrostatic piezoelectric properties of type 1-3 piezoelectric composites.

Lignin-derived porous carbon has been identified as a versatile electrode material for supercapacitors (SCs) in energy storage systems (ESSs) owing to their intrinsic advantages including good electrical conductivity, low cost, high thermal and chemical stability, and high porosity, which stem from high surface, appropriate pore distribution, tailored morphologies, heterostructures, and diverse derivates. In this review, to provide a fundamental understanding of the properties of lignin, we first summarize the origin, historical development, and basic physicochemical properties. Next, we describe essential strategies for the preparation of lignin-derived porous carbon electrode materials and then highlight the latest advances in the utilization of lignin-derived porous carbon materials as advanced electrode materials. Finally, we provide some of our own insights into the major challenges and prospective research directions of lignin-derived porous carbon materials for supercapacitors. We believe that this review will provide general guidance for the design of next-generation electrode materials for supercapacitors.

The copper current collector induces side reaction with metal sulphide due to copper sulphide formation while cycling. The carbon-coated aluminium foil was an ideal current collector in terms of inertness to metal sulphide anodes and low resistivity.

Owing to their high capacity and electrical conductivity, transition metal selenides have attracted attention as anodes for sodium batteries. In this study, CuSe was synthesised using a simple and scalable process that involved heating Se powder on a Cu current collector at 140 degrees C for 5 h. Furthermore, CuSe was used as an anode without a binder or conducting agent, exhibiting a stable capacity during long cycles. The initial capacity of the CuSe electrode was 289 mAh g(-1) at 15 A g(-1), which reduced to 89.2 % of the initial value after 10,000 cycles. During cycling, the CuSe particles were cleaved and pulverised into nanoparticles, which subsequently agglomerated to form a porous structure without capacity loss. This phenomenon is known as self-healing. Because pulverised CuSe exhibits optimal cycling properties, pulverisation does not cause poor cycling and can be overcome through self-healing. This study is the first to investigate the self-healing properties of metal selenides. Additionally, the Na3V2(PO4)(3)/CuSe full cell exhibited a good cyclability of 151 mAh g(-1) after 2000 cycles. The superior properties of CuSe in conjunction with an ether-type electrolyte provide deep insights for the development of long-lasting cycling batteries.