Rate Performance Research Articles

Dual Function of Sea Grapes (Caulerpa racemosa) As Phytoremediator for Palm Oil Mill Effluent and As Ornamental Fish Feed Formulation.

Phytoremediation is a promising technology for treating Palm Oil Mill Effluent (POME). Moreover, phytoremediators have the potential for various aplication, including as feedstock. Hence, this study aims to elucidate the ability of sea grapes (Caulerpa racemosa) in remediating POME and evaluate their suitability as ornamental fish feed. Results showed that application of sea grapes effectively decreased the COD, TSS, phosphate (PO43-), and nitrate (NO3-) levels in POME. Sea grapes maintained in POME with a concentration of 12.5% had the highest reduction rate and growth performance. Moreover, sea grapes biomass from the remediation process can be utilized as feed material for ornamental fish, as indicated by increasing skin coloration of fish. For the first time, this study provides sustainable options for managing POME using sea grapes and suggests sea grapes as a potential fish feed formulation for ornamental fish.

Overcoming volumetric capacitance-rate performance tradeoff with 0D/2D conductive carbon nitride/phosphorene heterostructure for flexible supercapacitor

Few-layer black phosphorus (FL-BP) is considered a rising star 2D material for flexible supercapacitors (FSCs) due to its exceptional properties, including mechanical flexibility and high active surface area. However, the disordered deposition of FL-BP nanoflakes often leads to face-to-face restacking, which diminishes the effective active area and ion transport channels. This poses a huge challenge in simultaneously achieving high volumetric capacitance and rate capability. To address this, a 3D porous 0D/2D FL-BP/conductive carbon nitride (FL-BP/c-CN) film has been developed. The introduction of 0D c-CN nanoparticles effectively prevents the restacking of FL-BP nanoflakes and expands the nanofluidic channels, thus facilitating charge transport and ions diffusion. Additionally, the highly conductive c-CN nanoparticles embedded into the FL-BP layers significantly improve overall conductivity. As a result, the FL-BP/c-CN film-based FSC demonstrates a remarkable rate performance, retaining 70% capacitance as the scan rate increases from 10 to 100 mV/s. Moreover, the incorporation of 0D c-CN nanoparticles increases the available space for charge accumulation, yielding a volumetric capacitance of 28.5 F/cm3 at a scan rate of 10 mV/s, which is three times higher than that of a pure FL-BP film electrode (9.2 F/cm3). This work presents an innovative approach for developing high-performance FL-BP-based FSCs.

Bismuth-based material with alveolar-like structure as advanced anode for superior potassium storage

Bismuth (Bi)-based anodes have a promising application in potassium-ion batteries (PIBs) due to their high theoretical capacity. However, Bi-based materials undergo unavoidable and drastic volume expansion during charging/discharging. In addition to this, the problem of poor reaction kinetics severely hinders its development. To solve these problems, we designed Bi2O3-Bi/Carbon hollow nanospheres (Bi2O3-Bi@CHNSs) inspired by the structure of alveoli and its contraction/expansion respiration mechanism. Bi2O3-Bi@CHNSs have an alveolus-like hollow core–shell structure and alveolus respiration-like reversible contraction/expansion mechanism for potassium storage, which provides good structural stability. In situ characterizations confirm that the Bi2O3 and Bi hybrid structures synergistically store potassium through a conversion/alloying mechanism. Bi2O3-Bi@CHNSs exhibited excellent rate performance as anode with a capacity of up to 270.4 mAh g−1 at a current density of 40 A g−1. Assembled as a full cell, the capacity reached 106.5 mAh g−1 at a current density of 30 A g−1, which is superior to most of the reported intact PIBs. This work utilized biomimetic design concepts to elaborate a bionic alveolar structure. It provides a new perspective for optimizing the volume expansion of Bi-based anodes and developing high-performance PIBs.

Deciphering the multi-electron redox chemistry of metal-sulfide electrode toward advanced aqueous Cu ion storage

While neutral aqueous metal batteries, featuring cost-effectiveness and non-flammability, hold significant potential for large-scale energy storage, their practical application is hampered by the limited specific capacity of cathode materials (less than 500 mAh g−1). Herein, capacity-oriented CoS2 and rate-optimized Co9S8 cathodes are developed based on the aqueous copper ion system. The charge-storage mechanism is systematically investigated through a series of ex-situ tests and density functional theory calculations, focusing on the reversible transitions of Co9S8→Cu7S4→Cu9S5/Cu1.8S and CoS2→Cu7S4→Cu2S, which are associated with the redox reactions of Cu2+/Cu+‖Co2+/Co and Cu2+/Cu+‖S22−/S2−, respectively. The electrochemical results show that CoS2 can exhibit a superior capacity of 619 mAh g−1 at 1 A g−1 after 400 cycles, while Co9S8 maintains an outstanding rate performance of 497 mAh g−1 at 10 A g−1 (the retention rate is 95% compared to 521 mAh g−1 at 1 A g−1). As a proof of concept, an advanced CoS2//Zn hybrid aqueous battery demonstrates a working voltage of 1.20 V and a specific energy of 663 Wh kgcathode−1. This work provides an alternative direction for developing sulfide cathodes in energetic aqueous metal batteries.

Coupled electrostatic induction strategy toward polyaniline-derived hard carbon with uniformly microporous boosts high-rate sodium storage

Constructing a uniform and controllable hard carbon anode with suitable micropores can effectively improve the overall sodium storage performance. Herein, an electrostatic induction strategy was used to change the structure of micelles by adding surfactant content to form polyaniline (PANI) with different morphologies. The presented synthesis method is characterized by the introduction of oppositely charged surfactants to induce rapid nucleation and the formation of foams with small pore sizes, which are then transformed into homogeneous microcellular pores by high-temperature carbonization. Thus, the microporous structures in hard carbon anode provide excellent electrochemical storage sites for sodium ion storage. As a consequence, the sodium dodecyl benzene sulfonate (SDBS) electrostatic induced PANI-derived hard carbon (SD-HC) showed a uniform pore structure with low surface area (14.54 m2 g−1) and uniform micropores (1.54 nm), which used as an anode material for sodium storage can provided high reversible capacity of 282.4 mAh g−1 at 50 mA/g, excellent rate performance (196 mAh g−1 at 5 A/g) and cycling stability (93.3 % capacity retention after 1000 cycles at 1 A/g). This simple and efficient synthesis strategy provides an effective guide for the design of nanostructures for the preparation of similar functional polymeric materials.

NiCo alloy-decorated nitrogen-doped carbon double-shelled hollow polyhedrons with abundant catalytic active sites to accelerate lithium polysulfides conversion

Lithium-sulfur (Li-S) batteries have received significant attention due to their high theoretical energy density. However, the inherent poor conductivity of S and lithium sulfide (Li2S), coupled with the detrimental shuttle effect induced by lithium polysulfides (LiPSs), impedes their commercialization. In this study, we develop NiCo alloy-decorated nitrogen-doped carbon double-shelled hollow polyhedrons (NC/NiCo DSHPs) as highly efficient catalysts for Li-S batteries. The distribution of NiCo alloy on both the inner and outer shells provides abundant catalytic active sites, effectively adsorbing LiPSs, mitigating the shuttle effect, and promoting the conversion between LiPSs and Li2S, even at high sulfur loadings. This results in enhanced redox kinetics within the Li-S system. Moreover, the highly conductive carbon material framework, enriched with carbon nanotubes and graphitic carbon layers, can greatly promote the efficient electron transportation. Additionally, the improved ion diffusion rates benefiting from the hollow structure can also be realized. By harnessing these synergistic effects, Li-S batteries incorporating the double-shelled NC/NiCo DSHP catalysts achieved a high specific capacity of 1310 mAh/g at 0.2C and a superior rate performance of 621 mAh/g at 4C. Furthermore, excellent cycling performance with ultralow capacity fading rate of only 0.045 % per cycle after 800 cycles at 1C was achieved. When sulfur loading reaches 6 mg cm−2, a high capacity of 4.6 mAh cm−2 at 0.1C after 100 cycles further validates the practical potential of this design. This study presents an innovative approach to alloy catalyst design, offering valuable insights for future research of Li-S batteries.

Edge‑nitrogen/sulfur co-doping boost high potassium ion storage of carbon nanosheet anode materials

Potassium-ion batteries (PIBs) have garnered considerable attention as a potential alternative to lithium-ion batteries. However, the larger radius of K+ poses challenges, including slow kinetic processes and significant volume changes, which adversely affect the rate performance and cycling stability of electrode materials. Herein, N, S co-doped carbon nanosheets (xNS-HC) are synthesized as anode materials of PIBs by carbonization of citric acid and CH₄N₂S precursors in LiCl/KCl molten salts. Of these, 5NS-HC possesses a high N content of 20.19 at.% with 90.90 % of edge N-species and a S content of 2.53 at.%. The 5NS-HC material exhibits a high specific K+ storage capacity of 368.2 mAh g−1 at 0.1 A g−1, superior rate capability (106.1 mAh g−1 at 10 A g−1), and long-term cycling stability (205.8 mAh g−1 after 2800 cycles at 1 A g−1). In-depth analysis via in-situ XPS and DFT calculations reveals that the active sites doped with edge-N/S exhibit a profound affinity towards K+, thus contributing to the outstanding electrochemical K+ storage performance observed in 5NS-HC. The full cell of K0.4Mn0.9Li0.1O2·0.33H2O||5NS-HC exhibits a high specific capacity of 141.2 mAh g−1, supporting a high energy density of 147.1 Wh kg−1. These compelling results illustrate that edge-N/S co-doping can significantly enhance the K+ storage of carbon anode materials.

A near-single-ion conducting polymer-in-ceramic electrolyte for solid-state lithium metal batteries with superior cycle stability and rate capability

Composite solid-state electrolytes (CSE) represent a promising alternative to conventional porous separators and organic liquid electrolyte systems in commercialized lithium metal battery (LMBs), offering effective dendrite suppression, high interfacial compatibility and enhanced cycle life. This study introduces a polymer-in-ceramic electrolyte, which is synthesized by blending perovskite-type inorganic electrolyte Li1.5La1.5TeO6 (LLTeO) with polymethyl methacrylate (PMMA) and polyvinylidene fluoride (PVDF), denoted as PMMA/PVDF-LLTeO. The resulting CSE features a dense, non-porous structure, high mechanical strength, excellent thermal stability, and a broad electrochemical window. Notably, with the incorporation of a high ceramic filler content (up to 70 %), the CSE promotes a hybrid ion transport mechanism, yielding a near-single-ion conducting behavior with an ion transference number of 0.833, and a high elastic modulus of approximately 1 GPa. These attributes collectively contribute to the suppression of dendrite growth, as analyzed through multiphysics-based simulations. Li//Li symmetric cells using PMMA/PVDF-LLTeO-70 exhibit robust lithium stripping-plating stability, with a critical current density of 0.45 mA cm−2. Furthermore, the corresponding Li//LiFePO4 cells exhibit superior rate performance and cyclic stability, achieving over 150 cycles with a capacity retention rate of 92.2 % at high temperatures (60 °C). This research highlights the potential of the proposed CSE with high-temperature applications, significantly improving the safety and performance of LMBs

Evaluating the efficacy of strategies for silicon/graphite anodes in Li-ion batteries

Recent research has been focused on the utilization of silicon (Si) based anode for high-energy–density lithium-ion batteries (LIBs) owing to the high theoretical capacity of Si (∼ 3578 mAh g−1). To mitigate the intrinsic volume change of Si (∼ 300 %) upon cycling, research focused on the co-utilization strategy of Si with graphite anode (SiG) in the form of the blending (physical mixture of Si and graphite) and composite (building up material containing Si and graphite). However, the underlying mechanisms of the two strategies that cause different electrochemical results have not been thoroughly explored. In this study, we aimed to investigate the composite anode (C-SiG-650) and blending anode (B-SiG-650) with a specific capacity of ∼ 650 mAh g−1 in terms of electrochemical performance. The composite electrode exhibited a uniform distribution of SiG particles, which helps for faster Li+ ion transport into bulk, whereas the blending electrode exhibited aggregation of SiG particles, which impedes the Li+ ion transport into the bulk. As a result, the composite anode exhibited superior capacity retention and rate performance compared to the blending electrode. Moreover, the composite anode containing full-cell delivered a higher specific capacity of 162 mAh g−1 and capacity retention of 73.58 % after 100 cycles. This implies that directly utilizing composite anode with a low-capacity SiG particle is a promising way to achieve high volumetric energy density for commercial device applications.

In-situ growth of FeCo layered double hydroxide nanorods on MXene for high-performance supercapacitor electrodes

In the pursuit of clean energy solutions, supercapacitors have gained attention due to their exceptional energy storage capabilities. Layered double hydroxide (LDH), a notable material in this field, faces some challenges such as slow charge transfer speed and volumetric expansion. To tackle these issues, a novel FeCo-LDH/MXene composite was synthesized through in-situ hydrothermal growth of FeCo layered double hydroxide (FeCo-LDH) nanorods on MXene using ionic self-assembly, forming a three-dimensional (3D) composite with enhanced rate capability and cycling stability due to the synergetic coupling of MXene and LDH. The FeCo-LDH/MXene electrode significantly improves surface capacitance control performance and exhibits exceptional electrochemical performance, achieving a specific capacitance of 2058.2 F g−1 at 1 A g−1 and maintaining 1732.7 F g−1 at 10 A g−1, with 82.4 % capacity retention. Furthermore, the assembled supercapacitor delivers an energy density of 48.8 Wh kg−1 at 750 W kg−1 and 25.7 Wh kg−1 at 15000 W kg−1, demonstrating excellent rate performance, as well as 80.3 % capacitance after 5000 cycles at 2 A g−1, highlighting its durability. This advancement not only overcomes the specific capacitance challenge of MXene electrodes but also enhances the conductivity and cyclic stability of LDH, making FeCo-LDH/MXene a promising candidate for future high-performance energy storage applications.

Construction of foam-like carbon microspheres with controllable pseudo-graphitic domains: Synergistic enhancement of K-ion adsorption/intercalation storage

Hard carbon shows promise as a potassium-ion battery (PIB) anode, but its high capacity and rate property are limited by insufficient active sites and poor kinetics. Creating a porous channel structure offers an effective route, but such design often disrupts the development of intercalation sites critical for low-voltage plateau capacity, and may reduce the energy density of full cells. Herein, a staged pyrolysis strategy was developed to tailor foam-like carbon microspheres (FCMs) with controllable pseudo-graphitic domains by exploiting polymer with the temperature difference in pyrolysis. Such tactics perfectly retains abundant pseudo-graphitic domains and creates rich defect/pore structures, ensuring efficient K+ low-voltage intercalation and benefiting fast K+ transport. The optimized electrode exhibits balanced adsorption/intercalation capacity, delivering a large reversible capacity (386.7 mAh g−1 at 0.1C), outstanding rate performance (223.1 mAh g−1 at 4C) and excellent capacity retention (79.2 % over 2000 cycles at 4C). Additionally, the FCM-2//PTCDA full cell submits a high energy density of 198 Wh kg−1 and superb rate property/stability compared to same-type full cells. Tracked K-storage behavior confirmed the “adsorption–intercalation” mechanism and kinetic studies clarified that exact balance of defect, mesopore and pseudo-graphitic phase was crucial for the synergistic enhancement of adsorption/intercalation kinetics. This work opens up a unique method to tune the microstructure of hard carbon and offers design principles for developing practical anodes with synergistic storage behavior suitable for PIBs.

Enhanced cyclability of O3-NaNi0.33Fe0.31Mn0.36O2 by Mg and Cu synergistic doping with strengthened Mn[sbnd]O bonds

Among some practical O3-type layered oxide cathodes, NaNi1/3Fe1/3Mn1/3O2 (NFM) features a high specific capacity and moderate cyclability. However, sluggish Na+ transfer kinetics, low structural stability, and rapid capacity loss during long-term cycling, are still posing a challenge to commercial applications of this material. In this work, we propose a Mg and Cu co-doped O3-type NaMg0.02Cu0.02Ni0.33Fe0.27Mn0.36O2 (MC-NFM) with a stable structure and good cycling stability. It was found that the MnO bonds in MC-NFM are obviously reinforced by synergistic doping with small amounts of Mg and Cu, leading to enhanced structural robustness, decreased Na+ migration barrier, and delayed O3-P3 phase transition. As a result, longer cycle life and enhanced rate performance are achieved. MC-NFM can yield a specific capacity of 142.1 mAh g−1 at 0.1C and 116.0 mAh g−1 at 5C, and maintain 83.6 % of its initial capacity after 400 cycles at 1C. This work provides a promising design of O3-type cathode for sodium-ion batteries.

Hydrothermal synthesis of rGO-decorated NiMn2O4 nanoneedles for high-performance positive electrode in asymmetric supercapacitors

Pseudocapacitive electrode materials inherently have low electron conductivity, which prevents an energetic material from being fully utilised. We were able to produce effective hierarchical NiMn2O4/rGO composites, which provide an appealing solution to this issue. The composites were synthesised using a one-step hydrothermal approach. Due to the high electrical conductivity of reduced graphene oxide (rGO), the needles on plate like morphology of NiMn2O4, and the strong hold of dynamic materials to the current collector, the resulting hybrid electrodes exhibit a specific capacitance of 1628 Fg−1 at a current density of 1 Ag−1. They also demonstrate excellent rate performance and remarkable cycling stability, with a capacitance retention of 97.4 % after 10,000 cycles. In addition, the NiMn2O4/rGO//AC asymmetric supercapacitor (ASC) exhibits a peak energy density of 45Whkg−1 when operated at a power density of 3240 Wkg−1. The ASC device has an impressive ultralong cycling life, with a capacitance retention rate of 89.1 % after undergoing 10,000 charge/discharge cycles. The NiMn2O4/rGO composites provide a scalable production method and demonstrate outstanding electrochemical performance. This presents an opportunity to create innovative hybrid electrodes for enhanced supercapacitors.

Hydrothermal Formulation of Dy2MoO6@rGO Nanostructure for Supercapacitors

The exceptional intrinsic conductivity and structural stability of mixed transition metal oxides (MTMOs) make them a significant pseudocapacitive electrode for supercapacitors. However, a major challenge is their inappropriate structures facilitating extended cycling life and rapid Faradic redox reactions. The present research reports the hydrothermal combination of dysprosium molybdate (Dy2MoO6) with reduced graphene oxide (rGO) to advance the specific capacitance (Cs) and rate performance of supercapacitors. While comparing pure Dy2MoO6, the Dy2MoO6@rGO nanocomposite exhibits a higher Cs of 1118Fg−1 at a current density (j) of 1Ag−1 and retention capacitance of 83.7% after 10,000 successive cycles. The enhanced electrochemical performance of Dy2MoO6@rGO results from its advantageous features, such as high structural stability, greater reactive surface area, favorable ion adoption, and rapid ion/electron transfer rate during the redox phenomenon. Furthermore, the asymmetric supercapacitors (ASCs) employing Dy2MoO6@rGO as the positive and activated carbon (AC) as the negative electrodes presented a Cs of 282Fg−1 at a rate of 1Ag−1. When operated at 1.6V, the constructed Dy2MoO6@rGO//AC ASC achieves an outstanding energy density (Ed) of 19.2Whkg−1 and a power density (Pd) of 272.2Wkg−1. These outstanding findings suggest that the created nanostructures Dy2MoO6@rGO can be used in ultra-performance ASC devices. Moreover, the method simplifies developing efficient energy storage devices using MTMOs by enhancing capacitance and expanding the potential range in an alkaline electrolyte.

Achieving complete solid-solution reaction in layered cathodes with reversible oxygen redox for high-stable sodium-ion batteries

P2-type layered Mn-based oxides are promising cathode materials for sodium-ion batteries (SIBs), but it is still challenging to achieve both high capacity and stability because of complex phase transitions and irreversible oxygen release at high voltage. To address these challenges, an optimal P2-type Na0.67Mn0.8Cu0.15Ti0.05O2 (NMCT) cathode with a complete solid-solution reaction and reversible oxygen redox reaction over a wide voltage range was developed. The introduction of the Na–O–Ti configuration leads to fewer delocalized electrons on oxygen and thus enhances oxygen redox activity, while the high energetic overlap between O 2p and Cu 3d states and the increased Mn–O hybridization strengthen the rigidity of oxygen framework to achieve reversible and stable oxygen redox reaction. In addition, the reinforced TM–O interaction, combined with the ameliorated Mn3+ Jahn-Teller distortion and disrupted Na+/vacancy ordering, synergistically eliminate the undesired P2–OP4 phase transition and lead to a complete solid-solution reaction, which greatly facilitates Na+ transport kinetics and stabilizes structural integrity. As a consequence, improved rate performance and cycling stability are achieved for NMCT. Our present study provides a promising avenue for simultaneously utilizing the reversible oxygen redox activity and maintaining the structural integrity to accomplish the capacity-stability trade-off of Mn-based oxide cathodes for constructing practical SIBs.

Cu2SnS3/rGO nanocomposites with optimized pore structure for high-performance lithium-ion batteries

Developing advanced anode materials is essential for enhancing the rate performance and stability of lithium-ion batteries (LIBs), which is critical for meeting the demands for next-generation energy storage solutions. In this research, Cu2SnS3/rGO nanocomposites were synthesized via a rapid microwave-assisted one-step method, followed by post-synthetic annealing. The incorporation of reduced graphene oxide (rGO) not only significantly improves its electrical conductivity, but also effectively inhibits the agglomeration of CTS nanoparticles. The nanocrystal size in the CTS/rGO nanocomposites has been dramatically downsized, transitioning from the pristine CTS dimensions of 0.9–1.5 μm to a mere 100 nm. This downsizing is a critical advancement in the electrode, as it enhances the surface area and reactivity of the composite. The subsequent high-temperature annealing process shrinks the pore size in the CTS/rGO nanocomposite, decreasing from an average of 42.13 nm to a more confined range of 7.81 to 8.77 nm, depending on the annealing temperatures. Electrochemical testing reveals that the CTS/rGO-A nanocomposite annealed at 300 °C exhibits superior electrochemical performance to the unmodified CTS and non-annealed CTS/rGO composite. The performance is evidenced by an initial capacity of 1856.97 mAh g−1 at a current density of 1 A g−1 and retains a capacity of 1250.32 mAh g−1 after 500 cycles. To elucidate the underlying mechanisms governing the lithium ion diffusion kinetics, capacitance and diffusion behavior of the CTS/rGO-A electrode, advanced techniques such as galvanostatic intermittent titration technique (GITT) and rate cyclic voltammetry (CV) were utilized. These analyses revealed that the synergistic effect of an increased Li+ diffusion coefficient (DLi+), coupled with a notable capacitive contribution, is demonstrated to the enhanced electrochemical performance observed. Furthermore, the COMSOL Multiphysics simulation also indicates improved structural stability of CTS/rGO-A, attributed to minimized stress from volume expansion during discharge. The CTS/rGO-A nanocomposites, featuring enhanced electrochemical performance, coupled with a straightforward and efficient fabrication method, emerge as a promising material for scalable and practical energy storage solutions.

N-doped hierarchically porous carbon from lignite-derived residue for high-performance supercapacitor

Lignite-derived residue with cross-linked aromatic structure and heteroatom groups is an alternative and low-cost precursor for porous carbon. Herein, N-doped hierarchically porous carbon (NDHPC) was prepared by KOH activation from lignite-derived residue using ZnO as the template and dicyandiamide as the nitrogen source. The optimal NDHPC presents hierarchically porous stacked layered structure with high specific surface area (2648.18 m2/g) and contains abundant O/N functional groups, making it promising candidate as the electrode material. Introducing nitrogen can provide more pseudocapacitors and meanwhile improve the wettability of the NDHPC, thus enhancing electrochemical performance. The optimal NDHPC exhibits a high specific capacitance of 336 F g−1 at the current density of 0.5 A g−1 with good rate performance. Additionally, the assembled NDHPC symmetrical supercapacitor presents outstanding cycle stability with 96.2 % capacitance retention and possesses energy density of 7.85 Wh kg−1 at power density of 250 W kg−1. This study offers an effective and low-cost approach to fully utilize the organic matter in coal-derived residue for preparing supercapacitor electrode materials.

In-situ synthesis AgO/AgNPs composite as binder-free cathode for high-performance aqueous AgO-Al batteries

Aqueous AgO-Al batteries are promising systems due to their ultrahigh specific capacity, energy density, and stable output voltage. However, they still suffer from the low utilization and sluggish kinetics of the cathode. In this study, the binder-free AgO/AgNPs composites were synthesized in-situ using a simple electrodeposition method. Due to the excellent conductivity and rich mesoporous structure of AgO/AgNPs materials, the electron and ion transfer kinetics were enhanced, thereby improving the charge storage performance of the electrode. As expected, the AgO-Al battery with the optimized AgO/AgNPs composite cathode demonstrated excellent rate performance, achieving a high discharge capacity of 325.1 mAh g−1, and a stable operating voltage platform of 1.55 V at the current density of 1000 mA cm−2. The maximum energy and power density were 687 Wh kg−1 and 6.2 kW kg−1, respectively. This work presents an effective strategy for designing high-performance AgO electrode materials for AgO-Al batteries.

Stacked borophene-based electric double-layer supercapacitors

As an exceptional metallic Dirac material, borophene shows promise for superior mechanical and electronic properties, making it increasingly significant in electronics. Both theoretical predictions and experimental evidence underscore its potential in energy storage applications. However, due to existing limitations in synthesis techniques, the application of stacked borophene as flexible electrodes remains unexplored. This study aims to overcome these challenges by introducing an innovative in situ co-eutectic salt method for synthesizing AB-stacked hydrogenated borophene sheets. These sheets are then employed to fabricate large-scale electrodes and construct flexible electric double-layer supercapacitors based on borophene. The robust mechanical stability of stacked borophene facilitates significant improvements in interfacial characteristics and energy storage performance through rolling processes. This enhancement results in increased specific capacity, improved rate performance, and enhanced cyclic stability of thin-film electrodes. Specifically, the optimized borophene-based supercapacitor achieves a high specific areal capacitance of up to 417.3 mF/cm2 in an organic electrolyte at a current density of 1 mA/cm2, which represents a twofold improvement compared to non-stacked borophene structures. Remarkably, it retains over 88.3 % of this specific areal capacitance even at a high current density of 15 mA/cm2, demonstrating impressive rate capability. Furthermore, after 5000 charge–discharge cycles, the capacitance retention exceeds 89.3 %. This research is expected to catalyse the application and advancement of borophene in future flexible and portable electronic devices, highlighting its potential transformative impact in energy storage technologies.

One-step electrodeposited cracked-bark-shaped NiCoMoS on carbon cloth for high-performing aqueous asymmetric supercapacitors

The present study focuses on the development of a high-performing flexible electrode with a cracked-bark-shaped nanostructure of NiCoMoS (NCMS) on carbon cloth through one-step electrodeposition. The electrode demonstrates an impressive capacitance of 10,860.0 mF cm−2 at 1 mA cm−2 and superior rate performance, maintaining a capacitance of 4212.0 mF cm−2 even at 60 mA cm−2. Cycling test reveals that the electrode retains 86.2 % of its original capacitance and nearly 100 % Coulombic efficiency after 6000 cycles at 30 mA cm−2, attributed to the effective stress release facilitated by the cracked-bark-shaped structure. An aqueous asymmetric supercapacitor, comprising of NCMS cathode, activated carbon anode and 2 M KOH electrolyte, demonstrates an energy density of 0.600 mWh cm−2 at 0.800 mW cm−2 while exhibiting superior cycling stability (82.9 % after 15,000 cycles) at 30 mA cm−2.