Accurate State of Health (SOH) estimation is critical for battery management systems (BMS) in electric vehicles (EVs). However, the absence of a universal aging model for power batteries presents significant challenges. This study leverages the open-source battery cell data set from the University of Maryland and focuses on private battery packs to address the aging model SOH estimation. Two aging features indicative of capacity degradation are extracted from constant current charging data using incremental capacity analysis (ICA). To handle nonlinearity and feature coupling, a flexible data-driven aging model is proposed, employing dual Gaussian process regressions (GPRs) and transfer learning to enhance model efficiency and accuracy. Adaptive filtering via the Particle filter (PF) further refines the model by integrating aging features and output capacity, resulting in a closed-loop data fusion approach for precise SOH estimation. Battery pack aging experiments validate the proposed method, demonstrating that transfer learning effectively improves estimation accuracy. The proposed method achieves closed-loop SOH estimation with a mean root mean square error (RMSE) of 0.87, underscoring its reliability and precision.

Accurately estimating the battery's capacity over its cycle life is essential for ensuring its safety in applications, including transportation and the medical field, where specific power delivery is a key component for optimal output. Most research concerning lithium-ion health prediction utilizes current-voltage data or techniques that rely on modeling microscopic degradation. Acquisition of current-voltage data directly builds up degradation within the cell, and physics-based methods require high computational power. Recent research pivoted to using electrochemical impedance spectroscopy (EIS) for battery health prediction since it provides information-rich data while non-destructive to the cell. One major drawback of using EIS is the time it takes to acquire data, especially at lower frequencies where diffusion within the cell is prevalent. To address this, this investigation focuses on feature extraction, which creates a subset of data from a publicly available data set to contain the frequencies that are mostly correlated with degradation. Analysis shows that a simulated cell's state of health (SOH) can get as low as 0.94% MAPE using the two most correlated frequencies in the charge transfer (CT) region. This study provides a methodology to accurately predict the capacity and SOH while reducing the time needed to acquire EIS data by 93% for this case. This method also highlights the usefulness of a single-cell model for battery test bench applications.

Glass fiber (GF) is a widely used separator in zinc-metal batteries, and its geometrical configuration significantly affects the battery's cycle performance. However, the underlying mechanisms remain unclear. In this study, we examine how the separator's geometry influences battery cycle life, which is determined by the competition between internal short circuits caused by Zn dendrite growth and the deteriorated charge transfer during repeated electrochemical cycling—both of which are affected by the separator's configuration. As the dominance of these failure mechanisms varies with battery processing parameters (e.g., cycling current density and capacity), the systematic study presented here offers guidance for separator choice in Zn metal batteries.

This study introduces a novel composite cathode for aqueous zinc-ion batteries (ZIBs), leveraging porous basil-derived activated carbon (BAC) and nanostructured manganese dioxide (MnO₂) synthesized through a one-step hydrothermal process. For the first time, basil-derived carbon is integrated with MnO₂, resulting in enhanced electrochemical performance. The MnO₂/BAC composite delivers a remarkable specific capacity of 237 mAh/g at 0.5 A/g, along with an energy density of 314 Wh/kg and a power density of 0.66 kW/kg, outperforming cathodes made from pristine MnO₂ or BAC. These improvements stem from reduced particle size and a synergistic balance of capacitive and diffusive charge storage mechanisms. Density functional theory calculations corroborate the experimental results, revealing the composite's superior quantum capacity (158.7 µC/cm²) and quantum capacitance (80.4 µF/cm²). Stability assessments highlight excellent cycle life, with > 90% capacity retention and 100% Coulombic efficiency over 300 cycles. The exceptional performance is attributed to the material's unique nanostructure, high surface area (1090 m²/g), and optimized porosity. Additionally, practical applications of ZIBs in pouch cell form using the MnO₂/BAC cathode are demonstrated, showcasing its capability to power a toy car over a satisfactory distance. This study establishes a new benchmark for sustainable and cost-effective cathode materials, significantly advancing ZIB technology for high-efficiency energy storage applications.

Currently, the rapidly growing population is producing hazardous waste materials at an unprecedented rate, which seriously affects the global environment. Additionally, increasing population and pollution have amplified the need for renewable energy and efficient energy-storage technologies. One strategy is to implement greener processes for efficiency and/or utilize the waste generated for useful domestic and industrial applications. In this context, here, we harnessed the most littered environmental pollutant, cigarette filter waste (CFW), to synthesize carbon nanomaterials (CNM) via a single-step pyrolysis process, devoid of any catalyst or activating agent, possessing optimal characteristics for serving as an active electrode material in the fabrication of cutting-edge supercapacitors, thereby addressing the issue of waste recycling and the need for energy storage devices among the populace. Supercapacitors, namely SC-1 to SC-4 matching electrolytes, 1M H₂SO₄, 2M H₂SO₄, 1M KOH, and 2M KOH, fabricated using CNM electrodes were evaluated. Among these, SC-2 exhibits superior performance, demonstrating a remarkable capacitance of 240 Fg^-1 at low scan rates (2 mVs^-1), an enhanced energy density (22.4 Whkg^-1), and commendable power density (399.43 Wkg^-1). Furthermore, SC-2 maintained 5000 cycles of outstanding stability with 97.8% capacitance retention. This study unveils the potential of CFW-derived CNMs as an electrode material for the realization of state-of-the-art supercapacitors.

Bacterial cellulose (BC) as a natural polymer possessing ultrafine nanofibrous network and high crystallinity, leading to its remarkable tensile strength, moisture retention and natural degradability. In this study, we revealed that this BC membrane has excellent affinity to organic electrolyte, high ionic conductivity and inherent ion selectivity as well. Due to its ability of migrating lithium ions and suppressing the shuttling of anions across the membranes, it is deemed as available model for iodide-assisted lithium-oxygen batteries (LOBs). The cycle life of the LOBs significantly extends from 74 rounds to 341 rounds at 1.0 A g⁻¹ with a fixed capacity of 1000 mAh g⁻¹, when replacing glass fiber (GF) by BC membrane. More importantly, the rate performance improves significantly from 42 to 36 cycles to 215 and 116 cycles after equipping with the BC membrane at 3.0 and 5.0 A g⁻¹. Surprisingly, the full discharge capacity dramatically enhanced by ca. eight times from 4,163 mAh g⁻¹ (GF) to 32,310 mAh g⁻¹ (BC). Benefited from the convenient biosynthesis, cost-effectiveness and high chemical-thermal stability, these qualities of the BC membrane accelerate the development and make it more viable for application in advancing next-generation environmentally friendly LOBs technology with high energy density.

High-nickel ternary cathode (HNCM) materials are regarded as the primary choice for lithium-ion batteries (LIBs) due to their high energy density. However, their development is limited by lithium-nickel mixing, microcrack generation, and surface side reactions. Herein, a combined roll-to-roll and vacuum vapor deposition process is used to prepare LiNi_0.9Co_0.05Mn_0.05O₂ (NCM9055) cathode material with a dense, ultrathin, and robust lithium fluoride (LiF) protective layer. Compared with traditional methods, this approach allows precise control over the thickness and rate of the deposited LiF layer, producing a uniform and robust protective layer that enhances surface stability. This approach not only effectively reduces direct contact between the electrolyte and the electrode surface, mitigating corrosion and side reactions, but also strengthens the structural integrity of the cathode, thereby significantly improving cycling stability. The NCM9055 with a 10 nm LiF layer exhibits enhanced electrochemical performance, especially at cut-off voltages of 4.3 and 4.5 V, and also excellent cycling performance at 1 C. Additionally, the introduction of the LiF layer improves the thermal stability of NCM9055, further enhancing the safety of high-nickel batteries. This study not only demonstrates the combination of roll-to-roll processing and vacuum vapor deposition as a fast and effective modification technique but also highlights the advantages of vacuum vapor deposition in forming a homogeneous and robust LiF layer, which is essential for rapid production and for improving the safety and energy density of HNCM materials in advanced LIBs.

The growth of lithium dendrites has been regarded as the biggest challenge for lithium metal batteries (LMBs). Vertical graphene (VG) is a promising inhibitor against lithium dendrites. However, there is no research on the effects of various defect types of VG on LMBs. Herein, we grew different defect types of VG on copper foam as LMBs anode and then studied their electrochemical properties in detail. As the synthesis temperature increases, the density of carbon nanosheets (CNS) gradually rises, causing the VG to transition from vacancy-like type to boundary-like type. The cycling test shows that the boundary-like type electrode exhibits the highest coulombic efficiency exceeding 97.9% after 200 cycles at 5 mA cm⁻² among various defect type electrodes. The superior electrochemical performance of the boundary-like type electrodes is attributed to their high defect content and abundant edge defects, which provide numerous nucleation sites for lithium and promote uniform deposition. Additionally, the unique three-dimensional morphology of VG offers sufficient space for lithium deposition, effectively inhibiting the growth of lithium dendrites. This study highlights that boundary-like type VG can effectively enhance the stability of LMBs, and provides a new idea for the application of VG to the anode of LMBs.

With the expansion of off-grid hydrogen production systems, the randomness and volatility of renewable energy sources place higher demands on the power supply reliability of energy storage systems (ESS). This paper presents an adaptive hierarchical control (AHC) strategy for parallel energy storage units (ESUs) in electrolytic hydrogen production systems to improve the reliability of power supply. In this strategy, each ESU is considered an agent, and a dynamic average consensus algorithm is used to obtain the average value of the observed quantities. In the primary control layer, a sigmoid function is proposed to improve the droop coefficient, enabling the state of charge (SoC) of each ESU to converge to the average value. On this basis, a novel acceleration factor based on a normal distribution function is designed to accelerate the speed of SoC balancing in the later stage. In the secondary control layer, a unit virtual voltage drop balancing term and an average voltage compensation term are used to distribute the output current of ESUs proportionally according to their capacity and restore the average bus voltage deviation. The stability analysis confirms that the proposed method is strongly stable. Finally, a photovoltaic hydrogen production simulation model and a StarSim HIL experimental platform are established. The results show that the proposed control strategy can achieve rapid SoC balancing and accurate load current distribution with excellent average bus voltage compensation under various complex operating conditions.

Microgrids (MGs) are a solution to excessive load demand and power grid failure because they provide utility systems with stability and continuous power flow. A controller for a Fuzzy Logic System with neural network that is adaptable (Adaptive Fuzzy Neural Network Inference System) is suggested for a hybrid microgrid that is fueled by renewable energy sources. A modern high-gain Landsman converter is one of the numerous converters in use is employed to increase the solar output and achieve a steady DC-link voltage to provide outputs with high efficiency. The converter control is accomplished via the ANFIS method, a noteworthy substitute that combines two computational techniques: Neural networks and fuzzy set theory (ANN). Using the Crow Search Algorithm (CSA), the ANFIS constraints are reinforced to boost the convergence rate and dependability predictive accuracy rate. PWM-based rectification system controlled by a Proportional-integral control algorithm then links the wind system and microgrid configuration. When power from solar and wind sources is scarce, energy storage battery system (BESS) is used to hold energy for use in the DC connection. The MATLAB platform simulates evaluations of the control strategy. The proposed Landsman converter with high gain demonstrates superior energy efficiency compared to the Super Lift Luo converter, which in turn makes it a more effective solution for stabilizing DC-link voltage and boosting RES outputs in hybrid microgrid systems.

We highlight the lowest-temperature manufacturing of oxide-based all-solid-state batteries in this study. A lithium-rich oxychloride melt was employed to integrate Li_6.25Ga_0.25La₃Zr₂O₁₂ (Ga-LLZO) solid electrolyte particles and LiCoO₂ cathode-active particles at 350°C. As observed by X-ray diffraction, scanning electron microscopy, and microcomputed tomography, the infiltration and subsequent solidification of the melt can promote interparticle contact without chemical crosstalk in the cathode and across the cathode-solid electrolyte interface. The melt-infiltrated all-solid cathode exhibits respectable capacity, 83 mA h g⁻¹ at 90°C. Due to mechanical degradation of the interfaces, the cathode failed to maintain good cycle stability. Given that the minute amount of liquid electrolyte addition leads to substantial improvement of achievable capacity (106 mA h g⁻¹ at RT) and capacity retention, ensuring electric wiring in the cathode is key to achieving desirable electrochemical properties of the all-solid cells produced by the melt-infiltration process. Identified cathode optimization to better leverage this melt-infiltration approach includes, but is not limited to, engineering particle size distribution of Ga-LLZO and LiCoO₂ and configurations of the cathode components. While our proposed method is yet to be perfected, we have established a practical foundation to integrate oxide-based all-solid-state batteries.

Advancements in industry and technology, along with population growth and increasing demands for a comfortable lifestyle, have continuously driven up energy consumption. The depletion of conventional energy sources has increased interest in renewable and alternative energy sources. Renewable energy sources are types of energy that are continuously replenished in nature and are produced sustainably through natural processes. In recent years, PV technology has become one of the most preferred renewable energy systems due to its modular structure, easy installation, advanced technological level, and low operating costs. Energy storage units are crucial for ensuring that energy needs are met under all circumstances. Hybrid energy storage systems play a significant role in energy storage and enable the efficient use of resources. This paper discusses the development of a Hybrid Energy Storage System (HESS), consisting of a lithium-ion (Li-ion) battery and supercapacitor (SC). The designed system is integrated with a PV system to meet the energy requirements of a Brushless DC motor (BLDC).

Sodium batteries are a suitable alternative to lithium batteries due to the limited availability of lithium metal resources. Research on polymer electrolytes based on poly(methyl methacrylate) (PMMA) in sodium batteries has been limited. However, studies on PMMA-based polymer electrolytes in sodium batteries have shown that the use of fillers is an effective method for improving the ionic conductivity of PMMA. Another approach that can significantly enhance the conductivity of this type of electrolyte is the introduction of porosity into the electrolyte. In the present study, the electrochemical properties of a porous polymer electrolyte based on PMMA are investigated. The cross-linked PMMA-based gel polymer electrolytes (GPEs) are prepared via a photopolymerization technique, and the porosity of the prepared electrolyte is achieved through an etching method using a solvent. The results showed that the introduction of porosity enhances the ionic conductivity of GPEs in sodium-ion batteries. The optimized GPE exhibited an ionic conductivity of 1.56 mS cm⁻¹ at room temperature, excellent electrochemical stability (upper 4.5 V), and a specific capacity of 138.9 mAh g⁻¹. These findings highlight the potential of porous PMMA-based GPEs for the development of high-performance sodium ion batteries, offering a viable pathway toward next-generation energy storage technologies.

The energy management system (EMS) is becoming a focal point of research in the renewable energy sector, especially when integrating PV solar systems, BESS, and a standby diesel generator of a microgrid (MG). The EMS controls, monitors, and manages the power dispatch of different integrated sources based on the strategy that balances the demand with the supply, with the available energy sources related to solar and BESS. The EMS application strategy directly affects the BESS SOH and, thus, increases its operational remaining useful lifetime (RUL). Therefore, this study develops an intelligent EMS (iEMS) implemented within the MG based on predictive artificial neural network (ANN) control power dispatch strategy. The proposed iEMS has proved to be effective and accurate (MAE = 6.43%) which improved and optimized the BESS SOH through the prosecution of a 6-h prediction on blackout occurrence and noncritical load shedding. Consequently the iEMS preserved the SOH to 33% (an increase of 45% compared to classical EMS) and decreased the blackout occurrence by 56% (−5203 h) in contrast with the classical EMS where the SOH reached 20% and blackout occurrences totaled 11,899 h. This proves that the model is effective, and the control logic avoids high loads being dispatched from the BESS at critical time intervals where the AI model predicts a blackout occurrence.

Anode-less all-solid-state batteries (ASSBs) are emerging as promising candidates for next-generation energy storage, offering exceptional energy density, inherent safety, and streamlined manufacturability. However, their widespread adoption is hindered by the risk of internal short-circuiting stemming from the uncontrolled propagation of lithium (Li) dendrites, especially during high-current operation. This study introduces a nanoscale dual-layer lithiophilic architecture for the anode-less electrode—a gold (Au) film as the outer layer with a magnesium (Mg) layer underneath—to address this challenge. By exploiting the divergent electrochemical kinetics of these metals, Li nucleation is selectively confined to the underlying Mg layer, while the Au overlayer serves as a conformal barrier to mitigate dendrite penetration. The engineered interface enabled stable cycling with 81.4% capacity retention after 100 cycles at a high current density of 3.5 mA cm⁻² and room temperature (25°C), alongside robust operation in a pouch-cell configuration under a modest stack pressure of 4 MPa. These findings highlight the strategic importance of dual-metal lithiophilic designs with the ability to synergistically tailor the nucleation dynamics, as a scalable pathway for practical anode-less ASSBs.

Lithium-sulfur (Li-S) batteries offer high theoretical energy density, yet their practical application is limited by critical issues, including the polysulfide shuttle effect and irregular lithium deposition. To address these issues, we employ a natural protein, bovine serum albumin (BSA), to functionalize the commercial separator for enhancing the performance of Li-S batteries. The functionalization is prepared by well integrating denatured BSA and a polar polymer, poly(vinylidene fluoride-hexafluoropropylene) (PHFP), onto separators via a viable solution process. BSA features ionizable functional groups, imparts a negatively charged surface, enabling both the repulsion of polysulfides toward the cathode and favorable interactions with lithium ions at the anode interface. The PHFP matrix ensures mechanical integrity and thermal stability while maintaining the denatured conformation of BSA to expose its functional active sites. The resulting BSA-PHFP-modified separator exhibits enhanced electrolyte wettability, promotes uniform lithium-ion flux, and effectively mitigates shuttle-induced degradation. As a result, the modified separator enables Li-S cells to deliver a high initial discharge capacity of 782.1 mAh g⁻¹ and retain 414 mAh g⁻¹ over 500 cycles at 0.5 A g⁻¹. This study highlights the promise of bio-derived materials in designing multifunctional components in advancing high-performance Li-S battery systems.

Aqueous batteries are gaining attention owing to their high safety and cost-effectiveness. Among these, Zn-based aqueous batteries excel because of Zn's low redox potential (−0.76 V vs. SHE), its abundance, and eco-friendliness. However, despite their advantages, challenges, such as low energy density and limited cycle life limit their usage. This study addresses these issues by employing low-crystalline V₂O_4.86 as a cathode material, enhanced with oxygen vacancies created by controlled annealing time. The structure of low-crystalline V₂O_4.86 facilitates rapid structural transformation into the highly active phase Zn_3+x(OH)₂V₂O₇·2(H₂O). Electrochemical tests revealed a 22% capacity improvement for low-crystalline V₂O_4.86 (360 mAh g⁻¹) over high-crystalline V₂O₅ (295 mAh g⁻¹) at 0.8 A g⁻¹, attributed to the presence of active oxygen vacancies. Comprehensive structural analysis, spectroscopy, and diffusion path/barrier studies elucidate the underlying mechanisms for the first time, highlighting the potential of oxygen-engineered V₂O₅. These findings indicate that electrodes engineered with oxygen vacancies offer promising insights in advancing cathode materials for high-performance secondary battery technologies.

Lithium-ion batteries (LIBs) power electric vehicles through exceptional energy density but pose critical safety risks when mechanically compromised, particularly through nail penetration-induced thermal runaway. This review synthesizes experimental and modeling studies to establish the thermal runaway initiation hierarchy: (1) State-of-charge (SOC) (doubles thermal runaway probability at over 60% SOC), (2) cathode chemistry (thermal runaway propagation of LiNi_0.8Co_0.1Mn_0.1-based batteries is eightfold faster than that of LiFePO₄-based batteries), (3) nail properties (the possibility of short-circuit current of steel-based batteries is 40% higher than that of copper-based batteries), and (4) penetration dynamics (depth's impact is more than that of separator thickness in triggering cascading failures). Thermal runaway mechanisms involve synergistic electrochemical-thermal-mechanical coupling, where localized heating (higher than 1 × 10⁴ K/s) initiates separator collapse (80°C-120°C) and electrolyte decomposition (200°C). Mitigation strategies focus on mechanically graded separators (SiO₂/polymer composites: increasing 180% in puncture resistance); shear-thickening adhesives reducing impact forces by 35%-60%; halogen-free electrolytes within a 2 s self-extinguishing time; and solid-state architectures showing 0% thermal runaway incidence in nail penetration tests. Critical gaps persist in standardizing penetration protocols (velocity: 0.1-80 mm/s variations across studies) and modeling micro-short circuits. Emerging solutions prioritize materials-by-design approaches combining sacrificial microstructures with embedded thermal sensors. This analysis provides a roadmap for developing intrinsically safe LIBs that maintain energy density while achieving automotive-grade mechanical robustness (ISO 6469-1 compliance), ultimately advancing collision-resilient electric vehicle battery systems.

The interface problem caused by the contact between electrode and solid electrolyte (SE) is the main factor hindering the development of solid-state batteries. And adding liquid electrolyte (LE) at the interface to form a solid-liquid hybrid electrolyte is the common strategy. The ion transport kinetics at the SE/LE interface include an active role for the (de)solvation of ions, and the energy barrier for Li⁺ transport between the liquid and solid phases is closely related to the solvation capacity of the solvent. Herein, the influence of the solvation structure of the electrolyte itself on the interface is investigated. Compared to dimethyl carbonate (DMC), the lower Li⁺ binding energy of tetrahydrofuran (THF) is more easily desolvated at the solid-liquid interface, allowing the formation of abundant aggregates and the generation of inorganic-rich interfacial phases, leading to interfacial compatibility. Using the combination of polyvinylidene fluoride (PVDF)-based SPE and THF-based LE, the cycle performance and rate performance of LiFePO₄(LFP) |SPE|Li batteries are improved. The Li/Li symmetric cell can achieve stable cycling over 1000 h at a current density of 0.05 mA cm⁻², and LFP/Li half-cell retains 93% of its initial capacity after 100 cycles at 0.5 C. This study can provide inspiration for the design of solid-LE interface.

Lithium-sulfur batteries offer high theoretical energy density, affordability, and environmental friendliness, but lack commercial viability due to performance issues stemming from Li dendrite growth and the shuttle effect. In this study, we apply a positively charged amino acid in a surface coating for commercial polypropylene separators, endowing it with shuttle-inhibiting and anode-stabilizing functions. The amino acid-modified separator (A-PC@PP) features a nanocomposite interlayer of L-Arginine (Arg), polyacrylic acid (PAA), and carbon nanofibers (CNFs) to trap and convert polysulfides. Meanwhile, Arg and PAA functional groups introduced throughout the separator homogenize the flux of Li⁺, suppressing the growth of dendrites on the Li metal anode. Arising from these favorable functions, Li-S cells equipped with A-PC@PP separators show excellent rate capability (> 530 mAh/g at an ultrahigh current density of 5 A/g) and improved cycling stability (with a low decay rate of 0.068% per cycle for 500 cycles at 0.5 A/g). This study showcases the viability of a promising and abundant amino acid in addressing the critical issues of Li-S batteries.

All-solid-state batteries (ASSBs) with sulfide-based solid electrolytes (SEs) are promising next-generation lithium-ion batteries owing to their high energy density and safety. The composite electrode is crucial in electrochemical performance, and SE coating on the cathode active material (CAM) is an effective strategy for improving the composite electrode structure. However, despite the importance of conducting agents (CAs) in composite electrodes, their impact on the SE coating process has not been thoroughly investigated. Here, the effect of CA incorporation during the SE coating process on the morphology of the coating layer, composite electrode structure, and resulting electrochemical performance of ASSBs were examined. When the SE coating excluded CA (SE@CAM), a dense SE layer was formed on the CAM surface. By contrast, incorporating carbon black (Super P) during SE coating (SE-SP@CAM) resulted in a Super P-rich SE coating layer, reducing the active surface area and electrical conductivity of electrode and resulting in poor electrochemical performance. Meanwhile, incorporating vapor-grown carbon fibers (VGCF, 1D CA) during the SE coating process (SE-VGCF@CAM) resulted in the formation of VGCF-embedded SE coating layer. This enlarged the active surface area and facilitated electron conduction, yielding an electrochemical performance higher than that of SE-SP@CAM and comparable to that of SE@CAM. This study revealed the impact of CA incorporation during the SE coating process on the morphology of the coating layer and composite electrode structure. Furthermore, it emphasizes the importance of the mixing protocol and CA selection in electrode fabrication, offering valuable insights into developing high-performance ASSBs.

Rechargeable lithium-ion batteries (LIBs) have quickly become one of the most popular energy storage sources for electronic devices. The LIB cathode significantly affects the battery's energy density, safety, lifespan, and cost, and LIBs exhibit better chemical and thermal stability. Among various cathode materials, lithium iron phosphate (LiFePO₄) has gained significant attention due to its excellent safety, low toxicity, cost-effectiveness, and structural stability, making it a preferred choice for commercial and high-performance battery applications. However, the electrochemical performance of LiFePO₄ is strongly influenced by its morphology and nanostructure. This review provides a comprehensive analysis of hydrothermally synthesized LiFePO₄ nanomaterials, focusing on their structural, morphological, and electrochemical properties. A detailed discussion of 1D, 2D, and 3D LiFePO₄ nanostructures is presented, highlighting their impact on Li-ion transport, conductivity, and overall battery performance. Furthermore, the electronic structure of LiFePO₄ is examined for its charge storage mechanisms. A novel aspect of this review is the application of machine learning techniques to analyze specific capacity variations under different hydrothermal synthesis conditions and electrochemical parameters, offering insights into performance optimization. Finally, the global challenges, prospects, and research opportunities for LiFePO₄-based LIBs are discussed, providing a roadmap for further advancements in this field.

The increasing reliance on renewable energy sources, electric vehicles, and portable electronics has intensified the demand for advanced energy storage systems that are both efficient and sustainable. Among the critical components of these systems, electrode materials play a pivotal role in determining performance. In this context, bismuth vanadate (BVO) has emerged as a highly promising material, thanks to its distinctive structural and electrochemical properties. BVO offers immense potential across various energy storage technologies, including lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), zinc-ion batteries (ZIBs) and supercapacitors. Its unique characteristics, such as efficient ion intercalation and robust battery-like behavior, position it as an ideal candidate for next-generation devices. Recent advances in morphological optimization have further enhanced the specific capacitance and cycling stability of BVO-based materials, paving the way for significant progress in energy storage technology. Furthermore, innovative approaches, such as leveraging BVO's photocatalytic capabilities in ZIBs, offer a cost-effective and environmentally friendly route to energy storage. This review highlights the transformative potential of BVO as an electrode material, emphasizing its role in addressing the pressing need for energy storage technologies that support clean and renewable energy initiatives. Through detailed exploration, it underscores the adaptability and promise of BVO in shaping the future of sustainable energy solutions.

Hard carbon (HC), an amorphous carbon-based material, is a promising anode for sodium-ion batteries (SIBs) due to its sustainability and electrochemical performance. Direct carbonization offers a simple and energy-efficient synthesis route with relatively high initial coulombic efficiency (ICE), though often at the expense of capacity. To overcome this limitation, both pre-treatment and post-treatment strategies have been developed to enhance HC properties. pre-treatment methods modify structural characteristics during synthesis by increasing structural disorder, surface activity, and defect density. In contrast, post-treatment methods improve the electrochemical behavior of the final product, yet remain comparatively underexplored. These two approaches serve complementary functions and, when integrated, offer potential for optimizing performance. This review discusses the methodologies, benefits, limitations, and impact of various pre- and post-treatment strategies for HC anodes in SIBs. Advancing understanding in this area is essential for the development of high-performance and sustainable SIB technologies.

Capacity fading during cycling remains a significant challenge for silicon-based anode materials in Li-ion batteries. Amorphous, sub-stoichiometric silicon carbide (a-SiC_x) nanoparticles have proven to be more stable than pure silicon, albeit with lower lithiation capacities. The incorporation of carbon during the nanoparticle synthesis is highly effective in the suppression of crystalline phases during both synthesis and cycling. In this study, a-SiC_x materials with varying carbon concentrations (up to 22 wt.%) were produced via gas-phase synthesis in a hot-wall reactor. The primary objective is to understand the mechanism of carbon incorporation into the silicon particles, and secondly its impact on material properties and battery performance. Based on extensive materials science investigations and NMR analyses, we have determined that carbon is incorporated together with hydrogen, which further promotes amorphization. Furthermore, cycling analysis shows a strongly increased stability with 85% retention after 200 cycles for materials with more than 10 wt.% carbon, probably mainly due to a reduced buildup of internal resistances and reduced volume expansion. Furthermore, crystalline Si-Li-phases cannot be formed in this material during lithiation enabling deep lithiations, and Coulombic efficiency is increased. These results suggest that a-SiC_x is a promising alternative to pure silicon as an anode material.