The combined properties of reduced graphene oxide/polypyrrole (rGO/Ppy) have drawn a lot of interest in composite electrodes for supercapacitors. In this work, chemical bath deposition (CBD) method was used to develop rGO/Ppy composite thin films. The CBD method enables the synthesis of self-supported electrode materials, optimizing the physicochemical characteristics and promoting efficient charge transfer of electrodes for energy storage systems. The characterization of rGO/Ppy thin films by X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy revealed the presence of amorphous Ppy with a spherical morphology on rGO layers. The rGO/Ppy thin films exhibited remarkable electrochemical properties, obtaining 987 F g−1 specific capacitance at scan rate of 5 mV s−1 and retaining 87% electrochemical stability after 3,000 cycles. Moreover, an aqueous asymmetric supercapacitor device (rGO/Ppy//H2SO4//WO3) demonstrated a 61 F g−1 specific capacitance and 11 Wh kg−1 specific energy at 0.474 kW kg−1. This study reveals an easy method for enhancing Ppy charge storage capacity and cyclic stability through composition of rGO for supercapacitor applications.
Pseudocapacitors and redox capacitors are among the most promising candidates for high specific energy and power delivery owing to their rapid charge-discharge capability and excellent cyclic stability. In this work, high-performance, self-supported nickel cobalt tungstate electrodes are fabricated via a facile successive ionic layer adsorption and reaction (SILAR) method with varying nickel-cobalt ratios. The optimized nanospherical Ni0.25Co0.75WO4 electrode achieves a remarkable specific capacity of 785.72 C g−1 at 1.1 A g−1, nearly three times higher than that of pristine nickel tungstate and cobalt tungstate. Moreover, Ni0.25Co0.75WO4 exhibits excellent cycling stability, retaining 77% of its initial capacity even after 5,000 cycles at 4.1 A g−1. When assembled into a hybrid supercapacitor (HSC) with reduced graphene oxide (rGO) as the negative electrode, the device operates at 1.6 V and delivers a high specific energy of 50.41 Wh kg−1 at a specific power of 1.74 kW kg−1. These findings demonstrate that nickel cobalt tungstate is a promising electrode material for high-performance supercapacitors and highlight a cost-effective synthesis approach with outstanding charge storage capability.
The interfacial stability between electrolyte components and electrode materials plays a crucial role in the formation of the solid electrolyte interphase (SEI) in sodium-ion batteries. In this work, density functional theory (DFT) calculations are used to investigate the interface behavior and electronic interactions of five common electrolyte anions (PF6−, BF4−, ClO4−, FSI− and TFSI−) on MoS2 surfaces. To capture the influence of electrochemical conditions, the surface is analyzed under three different Na concentrations corresponding to 0%, 50%, and 90% electrode degree of sodiation. Multiple interface orientations are considered for each molecule to evaluate interaction energies, charge redistribution, electron localization function, work function, and electronic structure modifications at the interface. The results reveal distinct interaction mechanisms depending on the anion and sodium content. BF4− exhibits strong interaction at low Na concentration, which weakens significantly upon sodiation. ClO4− shows a reduction in interaction strength despite relatively similar charge redistribution, accompanied by changes in electron localization associated with Na. In contrast, PF6− does not form a stable interface configuration and undergoes reorientation with increasing Na, favoring interactions with intercalated Na rather than the MoS2 surface. TFSI− exhibits a strong dependence on molecular orientation, with more stable configurations associated with oxygen coordination. These findings provide atomistic insight into the evolution of interfacial interactions in sodiated MoS2 and their possible implications for SEI formation in sodium-ion batteries.
This study investigates the electrochemical properties of zinc hydroxide (Zn(OH)2) thin films synthesized through two distinct methods: chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR). Notable variations in crystallite size, morphology, and bandgap energy were observed between the films synthesized using two methods. Specifically, a reduction in crystallite size was evident in films produced via the SILAR method, accompanied by an increase in bandgap energy. Morphological analysis revealed that CBD-deposited films exhibited a needle-like structure, while SILAR-synthesized films displayed a microflower-like texture. Electrochemical characterization in a 2 M KOH solution indicated that the Zn(OH)2 needles and microflowers thin film electrodes achieved remarkable specific capacitances of 329 F/g and 179 F/g at a current density of 1 A/g, respectively. Furthermore, both films demonstrated impressive cycling stability, retaining 78% and 74% of their original capacitance after 3,000 cycles at a scan rate of 100 mV/s. The findings of this study elucidate the significant impact of growth methods on the electrochemical properties of Zn(OH)2 thin films, providing valuable insights for the advancement of materials science and electrochemistry.
The doping of metallic impurities into hydrated oxide structures is a suitable strategy to enhance the pseudocapacitive storage and improve the strength of electrode materials. In this work, we have prepared Mg-doped WO3·H2O nanoplates via a facile one-step wet-chemical synthesis route. The doping of Mg2+ ions effectively improved the electrical conductivity, electroactive sites, and ion diffusion kinetics of WO3·H2O while maintaining its layered hydrated structure. The rational doping of Mg in hydrated tungsten oxide (WOM5, ∼3% Mg doping) electrodes exhibited superior specific capacitance (158 F g-1 at 1 A g-1) behavior with higher b-values (0.82), enhanced redox activity, and improved charge storage kinetics than other compositions. Furthermore, the fabricated aqueous asymmetric device demonstrated excellent long-term cycling stability with improved coulombic efficiency up to 5,000 cycles. These results highlight Mg doping as an effective strategy for enhancing the electrochemical performance and stability of WO3·H2O-based supercapacitors.
The rapid growth of electric vehicles (EVs) has intensified the necessity for advanced battery management system (BMS) capable of ensuring safety, reliability and optimal performance of lithium-ion batteries (LIB). This study presents a comprehensive review and analysis of modern smart BMS architecture with a particular focus on the integration of artificial intelligence (AI) and machine learning (ML) techniques. Key functional aspects including state estimation, cell balancing, thermal management, fault detection, and predictive maintenance are critically examined. The role of AI/ML algorithms such as artificial neural networks, long short-term memory networks, support vector machines, and deep learning modes in enhancing sate of charge (SoC), state of health (SoH), and remaining useful life (RUL) is discussed in detail. Next, the study evaluates emerging trends such as FPGA-based edge implementation and IoT-enabled cloud integration for real-time monitoring and control. A comparative analysis of various AI/ML techniques highlights their pros, cons, and practical deployment challenges. The finding indicates that hybrid approaches combining model-based methods with data-driven algorithms offer the most promising pathway for next-generation BMS. This work provides valuable insight into current technological advancements and identifies key research gaps for the development of scalable, efficient and intelligent battery management solution. Based on a critical assessment of 120 research articles and review papers, this study provides a comprehensive system-level evaluation of AI/ML-enabled BMS for electric vehicles. Unlike previous reviews focusing on individual BMS functions, it integrates and critically compares state estimation, cell balancing, thermal management, fault diagnosis, predictive maintenance, intelligent charging, FPGA-based edge intelligence, and IoT-cloud-enabled battery monitoring while identifying key research gaps and future opportunities.
This study reports the fabrication and characterization of self-supporting SiOxCy/C composite electrodes for lithium-ion batteries, prepared via a sol-gel route combining silicon and carbon precursors with biomass-derived kapok fibers. The monolithic materials are directly implemented as binder-free electrodes by simple cutting, eliminating inactive masses such as binder and carbon black. Mechanical compression tests demonstrate that fiber incorporation transforms the material behavior from brittle fracture to compliant deformation with elastic recovery, which is key to accommodating volume changes during electrochemical cycling. The monolithic electrode outperforms its formulated powder counterpart, delivering a reversible discharge capacity of 1,070 mAh.g-1 after 100 cycles at 168 mA g-1 with a retention exceeding 100%. Surface fluorination using XeF2 significantly increases the initial discharge capacity to ∼2,380 mAh.g-1 by promoting electrolyte access to the smallest pores from the first cycle. While capacity retention over 100 cycles requires further optimization, this work demonstrates that binder-free monolithic shaping combined with controlled surface fluorination is a promising strategy for next-generation of silicon-based anodes.
The rapid expansion of robotics into unstructured, human-proximate environments has exposed fundamental limitations of conventional lithium-ion batteries, including safety risks from flammable electrolytes, insufficient energy density for extended untethered operation, and rigid form factors incompatible with emerging soft and structural robotic designs. Solid-state batteries (SSBs), which replace liquid electrolytes with solid ionic conductors, offer a compelling solution to these challenges. In this Perspective, we examine the unique power requirements of modern robotic systems and evaluate how the intrinsic properties of SSBs—non-flammability, wide temperature tolerance, bipolar stacking capability, and geometric versatility—address these demands. Critically, we demonstrate that a single commercial robot operating with hot-swappable battery packs consumes a cumulative battery capacity of 60–88 kWh over a 7–10 years service life—equivalent to the entire battery of one passenger electric vehicle (EV)—exposing a substantial and underappreciated battery demand from the robotics sector that grows in lockstep with the installed robot fleet. We survey the current state of oxide-, sulfide-, and polymer-based solid electrolytes through the lens of robotic applications, identify the critical challenges, and propose a roadmap for SSB–robotics convergence over the coming decade.
To transition from a proof of concept to a scalable system, a supercapacitor must deliver beyond just high cyclic stability. This work emphasizes energy density, power density, scalability, and specific capacitance to better address the demands of practical applications while remaining cost effective, employing a simple single-step process that significantly reduces overall cost. Among various electrode materials, transition metal oxides (TMO) are especially promising due to their structural diversity. From TMOs, α-Fe2O3 (hematite) is particularly known for its stable structure, low cost and abundant. Despite α-Fe2O3 being abundant and environmentally friendly, and having been explored in previous strategies, mostly rely on composites or structural modifications to achieve high specific capacitance. In this work, hematite has been synthesised via a simple hydrolysis-coprecipitation method and directly used as an electrode in a symmetric supercapacitor. The device was assembled using a CR2032 coin cell, with Whatman filter paper Grade 1 serving as a separator, 6 M KOH electrolyte, and Nafion as the binder. The device demonstrated a specific capacitance of 1452 F/g at 0.5 A/g. Notably, this performance was achieved without the use of additional material incorporation or nano-structuring, indicating that straightforward coprecipitation can also exhibit high specific capacitance in a scalable, cost-effective manner. These results confirm that hematite, when processed by a scalable wet chemical method, can deliver promising charge storage performance, providing a cost-effective pathway.
Understanding Li-ion transport through the solid electrolyte interphase (SEI) is essential for improving the stability of lithium-metal batteries, as nonuniform ionic transport through the inorganic SEI can promote spatially localized Li deposition and dendrite formation. In this work, we develop a deep-learning-assisted framework to model Li-ion transport across the inorganic SEI by combining density functional theory (nudged elastic band) calculations with graph neural network learning. A systematic diffusion dataset was first generated for eight major inorganic SEI compo-nents, namely, LiF, LiCl, LiBr, LiI, Li2O, Li2S, Li3N, and Li2CO3, covering both bulk (grain) diffusion and grain-boundary diffusion over representative low-energy surfaces and interfaces. This dataset includes homogeneous and heterogeneous interfaces (in-terfaces), providing a unified design space for Li-ion migration in SEI environments. A path-aware graph variational autoencoder (GVAE) was then used to learn latent representations of NEB trajectories, and the learned embeddings were incorporated one into a predictive GNN model for minimum-energy-path and migration-barrier estimation. The combined GVAE-GNN framework achieved strong predictive performance for both grain and grain-boundary diffusion, with test-set R2 values of 0.93 and 0.94, respectively. Feature-importance and latent-space analyses further show that migration behavior is governed not only by composition, but also by local structural factors such as exposed surface, saddle-point character, and grain-boundary energetics. The results reveal clear transport trends across SEI chemistries, with halide-rich systems generally associated with narrower low-barrier distributions, while Li3N, Li2CO3, and structurally mismatched heterogeneous interfaces exhibit broader and higher-barrier landscapes. This study give a physics-informed machine-learning framework for Mapping and predicting Li-ion migration in complex SEI structures and provides insight into how SEI chemistry and microstructure jointly control interfacial ion transport.
Aluminum-air (Al-air) batteries are considered promising candidates for electrochemical energy storage due to their theoretical energy density (∼8,100 Wh kg-1), specific capacity (∼3000 mAh·g-1), low cost and the natural abundance of aluminum. However, several hurdles must be overcome before their widespread application. Notably, the aluminum anode is prone to passivation and corrosion, which reduces the effective utilization of the metal. In addition, the sluggish oxygen reduction reaction (ORR) affects the air cathode and significantly decreases the electrochemical performance of the system. These problems are mitigated with different strategies: the aluminum anode is usually coated with other metal elements to improve the battery performance. On the other hand, different materials have emerged to improve the oxygen reduction reaction activity in the air cathode, such as metal-organic frameworks (MOFs). In this mini-review, the challenges and recent advances in aluminum-air technology are examined, highlighting the use of metal-organic frameworks as catalysts for the air cathode and the application of different coating strategies to improve the stability and performance of the aluminum anode.
The relationships among deep learning, edge computing, artificial intelligence (AI), and the most recent advancements in digital twin (DT) technology for battery energy storage systems are discussed in this paper. The study highlights the need for improved cloud-edge coordination, AI model development, and stronger cybersecurity features by demonstrating real-world applications of digital twin technology in electric vehicles (EVs), aircraft, and grid storage. It also described DT-based structures for fault detection, real-time monitoring, and optimization through standardization and battery management system (BMS) fusion. Because DT-based solutions for distributed energy resources (DERs) offer improved energy management systems, various studies have been conducted on them. Better predictive maintenance results, greater operational resilience, and longer system lifespan are facilitated by the strategic digital transformation advancements of adaptive modeling, federated learning, and mixed-reality applications.
Composite solid-state electrolytes (CSSEs) represent a promising pathway toward advanced sodium metal batteries (SMBs), which are crucial for meeting the demand for higher energy density in electric vehicles and devices. However, the overall performance of SMBs, particularly in terms of safety and stability, remains below expectations due to limited ionic conductivity and interfacial uneven Na deposition. Herein, we develop an innovative composite solid-state electrolyte system that selects NASICON-type Na3.7Zr1.45Sc0.4Mg0.15Si2PO12 (NSMZSP) as an inorganic filler for incorporation into a polyvinylidene fluoride (PVDF) organic matrix. The optimized PVDF@NSMZSP CSSE creates multiple ionic transport channels along the PVDF, NSMZSP, and PVDF/NSMZSP interfaces, thus effectively promoting Na+ transport dynamics and optimizing the electrolyte/electrodes interface compatibility. An exceptional ionic conductivity of 5.5 × 10−4 S cm-1 at room temperature and a high Na+ transference number of 0.56 can be achieved accordingly. Full Na//Na3V2(PO4)3 cells employing this electrolyte deliver excellent rate capability and long-term cycling stability, maintaining a high initial discharge capacity of 95.7 mAh g-1 at 0.5 C, with a capacity retention of 95% after 200 cycles. This work demonstrates a promising CSSE system with fast ionic transportation, improved interfacial stability and sustainable cycle life, inspiring the construction of next-generation SMBs with well-designed CSSEs in the field of energy storage technology.
Safety concerns, particularly related to fire and explosions, remain a critical limitation of lithium-ion batteries (LIBs). In this study, we propose an effective approach for enhancing the safety of LIBs while minimizing the degradation of their electrochemical performance by employing an aluminum (Al) current collector coated with a melamine polyphosphate (MPP) layer exhibiting fire-extinguishing properties. The MPP layer, composed of MPP, polyvinylidene fluoride (PVdF), and carbon black, generates phosphorous radicals (PO and HPO) derived from the thermal decomposition of MPP above 400 °C, which enables fire extinguishment by scavenging combustible OH and H radicals. The cathode prepared with an MPP layer exhibits improved self-extinguishing time and comparable electrochemical performance in LIBs compared to those of the cathode prepared with pristine Al in optimized conditions based on the physicochemical properties of the MPP safety layer.
Ni-rich cathode materials have attracted significant attention as high energy density cathodes for lithium-ion batteries. However, Ni-rich cathode materials with a Ni content exceeding 80% have encountered challenges such as electrolyte side reactions due to the instability of Ni ions. These issues lead to rapid capacity fading and undermine battery stability. To address these problems, surface coating techniques have been widely employed. Among these methods, wet coating techniques have been commonly used. However, this approach leads to the unintended formation of a NiO-like phase due to water exposure, which accelerates cation mixing and degrades electrochemical performance. In this study, a dry coating method that excludes the influence of water was employed to enhance the surface stability of Ni-rich cathode materials. This enhanced stability is attributed to the suppression of NiO-like phase formation on the surface of the dry coated cathodes, which prevents cation mixing during cycling, avoids capacity degradation, and prolongs battery cycle life. Experimental results demonstrated significant differences between dry coated and wet coated Ni-rich samples based on LiNi0.8Co0.1Mn0.1O2 (NCM811). The capacity retentions of dry coated and wet coated NCM811 at 0.5C at 150 cycles were 80.8% and 73.4%, respectively. This result demonstrates that dry coating offers a statistically significant improvement in long-term capacity retention, reflecting a 10% enhancement in stability compared to conventional methods. Rate capability was evaluated by cycling at incremental rates from 0.2C to 20C (3 cycles per rate) followed by an additional 150 cycles at 0.5C. The results demonstrated that the dry coated sample exhibited a more pronounced and stable rate capability across all tested conditions compared to the wet coated sample. These findings confirm that the absence of NiO-like phase formation contributed significantly to enhancing the electrochemical performance, particularly in terms of stability and long-term reliability.
Development of advanced battery technologies for electric vehicles (EVs) has primarily focused on achieving high energy density, non-flammability, and fast charging capability. While commercial batteries have served as the backbone for EVs, numerous material challenges still remain to achieve these desired advancements. This perspective presents an overview of state-of-the-art strategies and recent breakthroughs aimed at overcoming the limitations of next-generation EV batteries.
Due to the rising price and limited resource supply chain of Li [NixMnyCoz]O2 (x + y + z = 1) (NMC) cathode material, lithium-ion battery (LIB) recycling technologies have been emerging as the best solution to address the price issue. Mainly, conventional hydrometallurgy processes have been applied to the LIB recycling field in recognition of its value. One remarkable advantage of the hydrometallurgy method is that it serves as a bridge to enable the Hydro-to-Cathode® method. However, using recycled raw materials in the production of precursor cathode materials needs to be studied in parallel with the impurity (dopant) effect. The insufficient selective impurity removal technology leads to unexpected electrochemical properties in the final NMC cathode active material, which can be doped by several different impurities. Consequently, scrutinizing dopant elements (inorganic and organic) is critical if we want to consider the Hydro-to-Cathode® method as a major recycling process of NMC cathode material.
The recognition of the importance of nanostructures is mainly due to the development of nanotechnology. For further developments in materials sciences, a concept that integrates nanotechnology with material chemistry to fabricate functional materials has to be proposed. Nanoarchitectonics will carry out this task. In nanoarchitectonics, we architect functional material systems from nano-units (atoms, molecules, nanomaterials). The methodology is not specific to any particular material or application. It covers a wide range. Therefore, nanoarchitectonics can be thought of as the method for everything in materials science. As typical demonstrations for usages of nanoarchitectonics, this review paper presents our work on nanoarchitectonics for supercapacitors. We divide it into two categories with different approaches. The first is the development of carbon materials as supercapacitor electrode materials from biomass. The second category is preparing carbon materials using structures created by supramolecular assembly of fullerenes such as C60 and C70. By presenting examples using opposite starting materials, a complex natural material, and an ultimately simple molecule, we will demonstrate the versatility and breadth of possibilities of this approach.
The advancement of Mn deposition/dissolution chemistry and its translation to different battery variants is progressively documented. However, Mn represents poor reversibility, causing limitations for practical application. With the purpose of improving Mn-based battery operation, various technical solutions have been implemented for numerous batteries with Mn deposition/dissolution chemistry. This review summarizes the rapid advancements on Mn deposition/dissolution chemistry-based aqueous batteries.
Organic ionic plastic crystals (OIPCs) are promising for developing safer energy storage electrolytes. However, there remains a significant knowledge gap regarding how different cation-anion combinations influence their core properties, and cyclic ether-based cations have received limited attention. This study reports the synthesis and characterization of OIPCs based on the N -ethyl- N -methyl-oxazolidinium cation [C 2 moxa] + and demonstrates the first instance of oxazolidinium OIPCs being combined with lithium salts to create electrolytes. The [C 2 moxa] + cation was paired with [FSI] - , [TFSI] - , [BF 4 ] - , [PF 6 ] - and [FTFSI] - anions. A study of the thermal, transport and electrochemical properties was performed. Among the new salts developed, [C 2 moxa][BF 4 ] exhibited the most promising characteristics, including the lowest entropy of melting (ΔS = 7 J mol −1 K −1 ), an extended phase I range (10°C–130°C), the highest conductivity of 8 x 10 −6 S cm −1 at 30°C, and an electrochemical stability window of 4.8 V. When the [C 2 moxa][BF 4 ] and [C 2 moxa][FSI] were mixed with lithium salts (10, 20 and 50 mol% Li + ) of the same anion, the highest conductivity of 2 x 10 −3 S cm −1 at 30°C was found for the 20 mol% LiFSI/[C 2 moxa][FSI] electrolyte. Finally, preliminary lithium plating/stripping experiments and coulombic efficiency (CE) measurements demonstrate stability for lithium cycling for all four [C 2 moxa] + electrolytes.
