Cycling Retention Research Articles

Engineering conductive carbon networks within hollow structure: A wire-in-tube Co9S8/C@C composite for efficient K-ion storage

Hollow structured composites show great promising to accommodate the large volume fluctuation of high-capacity anodes with good structure integrity, while it still suffers from insufficient charge transportation due to the intrinsic low conductivity of anodes and the limited transport channels within hollow structure. Herein, conductive carbon networks are rationally constructed within hollow structure to realize both excellent structure stability and superior charge transportation. By encapsulating MOF-derived Co9S8/C wires into hollow carbon tubes, as-prepared wire-in-tube (WIT) Co9S8//C@C composite manifests exceptional potassium storage performance. It displays excellent cycling retention and maintains high capacities of 410 mA h g−1 at 100th cycle under 0.1 A/g and 201 mA h g−1 after 1500 cycles at 1 A/g. It also achieves a superior rate capability of 200 mA h g−1 at 10 A/g, surpassing most cobalt sulfide-based anodes that have been reported for PIBs. As revealed by in-depth characterizations and theoretical calculation, the conductive network engineering within hollow structure can optimally augment the electron/ion conductivity of Co9S8 and tolerate its volume changes during cycles, thus leading to the exceptional performance of WIT Co9S8//C@C composite.

Electrochemical Properties of Li4Ti5O12 Coated LiMn0.6Fe0.4PO4 Prepared by Rheological Phase Reaction Method

Abstract In this study, we fabricated LiMn0.6Fe0.4PO4/C (LMFP/C) materials employing the spray drying method. Subsequently, the LMFP/C composites underwent surface modification with Li4Ti5O12 (LTO) using the rheological phase reaction method. LTO demonstrates high electrochemical activity and possesses significantly greater lithium-ion conductivity compared to LMFP. The developed composite coating serves a dual purpose by safeguarding the LMFP material against electrolyte erosion and facilitating the swift transfer of lithium ions and electrons. The results from transmission electron microscopy and energy-dispersive X-ray spectroscopy validated the successful coating of LTO onto the LMFP/C surface after the surface modification treatment. A comparative analysis was conducted between the pristine LMFP/C powder and the LMFP-LTO composite that underwent surface modification. The results reveal that the 2 wt. % LTO-coated LMFP/C composite has the best electrochemical performance, manifesting specific capacities of 156 and 132.6 mAh·g-1 at 0.2 and 5 C rate, respectively. Furthermore, the material demonstrated excellent cycle retention, with 95.4% capacity retention after 100 cycles at 1 C. Hence, LTO coating can be considered an efficacious strategy for enhancing the electrochemical performance of LMFP.

Preserving the structural stability of LiNi0.92Co0.04Mn0.04O2 cathode by Ti4+-ion doping for lithium-ion batteries

Given the exponential rising demand for high-performance lithium-ion batteries (LIBs), Ni-rich layered LiNixCoyMn(1-x-y)O2 (LN) cathode materials have gained significant attention. Nevertheless, poor structural stability of LN cathode materials is a critical hurdle to their use in LIBs. In this regard, Ti-doped LN cathode materials are designed to enrich the structural reliability of LN cathode materials, and their underlying behaviors are elucidated. Once Ti is replaced in the layered sites of the LN cathode materials, it strongly binds to lattice oxygen owing to its outstanding binding affinity. Therefore, Ti-doped Ni-rich LN cathode materials exhibit increased thermal stability and mechanical rigidity compared with bare LN cathode materials. In terms of cycling behavior, the Ti-doped Ni-rich LN cathode materials deliver remarkably improved cycling retention; the 2.0% Ti-doped Ni-rich LN cathode material yields an 88.0% retention, while the bare Ni-rich LN cathode material yield a 52.2% retention after 100 cycles. Further analyses of the recovered Ni-rich LN cathodes indicate that structural deformations, such as microcracks and phase transitions, are evidently suppressed in the Ti-doped LN cathode, and additional parasitic reactions, such as electrolyte decomposition, are also inhibited after cycling. This means that incorporating Ti in Ni-rich LN cathode materials not only suppresses structural deformation but also simultaneously increases the interfacial stability upon cycling, thus leading to a comprehensively improved cycling behavior.

Exploring the potential of Withania somnifera-mediated Ag/Mn3O4 nanocomposites as electrode material for high-performance supercapattery device

Background: In this work, a bioengineered symmetric electrode material (anode, cathode) for energy storage devices was successfully demonstrated. Methods: Using Withania somnifera, Ag/Mn3O4 nanocomposite was prepared through sol-gel-assisted green synthesis. Physicochemical properties of Ag/Mn3O4, 431 nm (Ag), 315 nm (Mn3O4) in UV–visible analysis, metal (Ag) and metal oxide (Mn3O4) bonds, crystallinity index with a crystallite size of ∼29 nm from the XRD studies, rod-like morphology (SEM analysis), elemental composition (EDAX analysis), and chemical states (Ag 3d and Mn 2d) were identified through XPS studies. Significant findings: The cyclic voltammetry profiles of Ag/Mn3O4 exhibit the supercapattery behaviour with a specific capacitance of 254 F/g at a scan rate of 5 mVs−1 and a cyclic retention of 92.3 %. The fabricated symmetric supercapattery device (SSD) has an energy density of 18.5 Whkg−1 and a power density of 2084 Wkg−1. The stability of the complex is also studied in theoretically.

Simultaneous Realization of Multilayer Interphases on a Ni-Rich NCM Cathode and a SiOx Anode by the Combination of Vinylene Carbonate with Lithium Difluoro(oxalato)borate.

Ni-rich NCM and SiOx electrode materials have garnered the most attention for advanced lithium-ion batteries (LIBs); however, severe parasitic reactions occurring at their interfaces are critical bottlenecks in their widespread application. In this study, an effective additive combination (VL) composed of vinylene carbonate (VC) and lithium difluoro(oxalato)borate (LiDFOB) is proposed for both Ni-rich NCM and SiOx electrode materials. The LiDFOB additive individually delivers inorganic-rich cathode-electrolyte interphase (CEI) and solid-electrolyte interphase (SEI) layers in anodic and cathodic polarizations before the VC additive. Subsequently, the VC additive is capable of the formation of additional CEI and SEI layers composed of relatively organic-rich components through an electrochemical reaction; thus, inorganic-organic hybridized CEI and SEI layers are simultaneously formed at the Ni-rich NCM and SiOx electrodes. Accordingly, the VL-assisted electrolyte exhibits remarkably prolonged cycling retention for the Ni-rich NCM cathode (86.5%) and SiOx anode (72.7%), whereas the standard electrolyte shows a substantial decrease in cycling retention for the Ni-rich NCM cathode (59.2%) and SiOx anode (18.1%). Further systematic analyses prove that VL-assisted electrolytes form effective interphases for Ni-rich NCM and SiOx electrodes simultaneously, thereby leading to stable and prolonged cycling behaviors of LIBs that offer high energy densities.

Data-driven unlocking volume conservation in single-crystal Ni-rich layered oxides

Our study redefines anisotropic lattice variation through volume conservation (VC) in single-crystal (SC) Ni-rich layered oxides to facilitate long-term cycling stability. Data-driven analysis of the correlation heatmap of the five covariate variables and cycling retention enables precise cut-off voltage modulation for high-energy-density Ni-rich cathodes. We establish the anisotropic variation between a and c lattice constants as critical, leading to interfacial microcracks formation in degrading cycling retention. A balanced use of this variation, verified through computational models, Li1−x[Ni10/12Co1/12Mn1/12]O2 (NCM) and Li1−x[Ni10/12Co1/12Ti1/12]O2 (NCT), creates a volumetric stress free state at the inflection point. Unfortunately, two-scale challenges, namely macroscopic and local structure lattice misfits, which trigger intragranular microcracks, remain unresolved. Formation energy diagrams show biphasic reaction causing macroscopic lattice misfit based on the lattice direction occurring below x = 0.75 in both cathode models. Its effect can be mitigated by doping Ti into the Ni-rich material. Atomistic misfits of in-plane and out-of-plane directions are observed. Furthermore, MO2 and LiO2 slabs anisotropically vary in the complexes for NCM and NCT. Moreover, Ti-doped layered oxide clearly reduces local structural misfits and anisotropy. The proposed VC holds potential as a universal parameter for durable Ni-rich layered oxide fabrication for lithium-ion batteries.

A composite material consisting of tin nanospheres anchored on and embedded in carbon nanofibers for outstanding sodium-ion storage

Benefiting from the abundant availability of sodium resources and the relative lower cost, sodium-ion batteries (SIBs) are increasingly garnering attention. However, there is a pivotal challenge in contemporary battery research, revolves around the advancement of electrode materials that are both high-performing and abundant in nature. Sn-based materials stand out as promising anodes in SIBs owing to the high theoretical capacity (847 mA h g−1) of metallic tin. Herein, a composite of Sn nanospheres anchored on and embedded in the carbon nanofibers (Sn@CNFs) has been synthesized by electrospinning and the following annealing process. After that, the Sn@CNFs was directly used as free-standing anodes for sodium-ion batteries. Remarkably, with assistance of K+ in the electrolyte, the Sn@CNFs anode sustains a capacity of 470.3 mA h g−1 over 450 cycles with a superb Coulombic efficiency (CE) of 99.71 %. Additionally, with a high cycle retention of 99.0 %, the Sn@CNFs||NVP full-cell delivers high charge and discharge capacity of 100.7 and 99.8 mA h g−1 at 0.1C after 50 cycles.

Optimized In Situ Doping Strategy Stabling Single-Crystal Ultrahigh-Nickel Layered Cathode Materials.

Single-crystal Ni-rich cathodes offer promising prospects in mitigating intergranular microcracks and side reaction issues commonly encountered in conventional polycrystalline cathodes. However, the utilization of micrometer-sized single-crystal particles has raised concerns about sluggish Li+ diffusion kinetics and unfavorable structural degradation, particularly in high Ni content cathodes. Herein, we present an innovative in situ doping strategy to regulate the dominant growth of characteristic planes in the single-crystal precursor, leading to enhanced mechanical properties and effectively tackling the challenges posed by ultrahigh-nickel layered cathodes. Compared with the traditional dry-doping method, our in situ doping approach possesses a more homogeneous and consistent modifying effect from the inside out, ensuring the uniform distribution of doping ions with large radius (Nb, Zr, W, etc). This mitigates the generally unsatisfactory substitution effect, thereby minimizing undesirable coating layers induced by different solubilities during the calcination process. Additionally, the uniformly dispersed ions from this in situ doping are beneficial for alleviating the two-phase coexistence of H2/H3 and optimizing the Li+ concentration gradient during cycling, thus inhibiting the formation of intragranular cracks and interfacial deterioration. Consequently, the in situ doped cathodes demonstrate exceptional cycle retention and rate performance under various harsh testing conditions. Our optimized in situ doping strategy not only expands the application prospects of elemental doping but also offers a promising research direction for developing high-energy-density single-crystal cathodes with extended lifetime.

Investigation of surfactant assisted Fe2(MoO4)3/rGO nanocomposite for supercapacitor application

Utilizing a hydrothermal method with PEG-6000 as a surfactant material, this study presents the synthesis of Fe2(MoO4)3 nanoparticles and their nanocomposites with carbonaceous material in the form of rGO. Comprehensive fundamental characterization studies, including XRD, Raman, and FTIR, confirm the monoclinic crystal structure of Fe2(MoO4)3 and its nanocomposites. Nanorod-structured Fe2(MoO4)3/PEG/rGO exhibits a surface area of 78.571 m2/g with pore volume of 0.202 cc/g. Electrochemical analyses, employing techniques such as Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS), underscore the remarkable performance of the synthesized electrodes. Notably, the Fe2(MoO4)3/PEG/rGO electrode exhibits a specific capacitance of 575.13F/g at a scan rate of 10 mV/s and demonstrates significant cyclic retention over 20,000 cycles at a current density of 20 A/g in GCD analysis. This work highlights the promising electrochemical attributes of Fe2(MoO4)3/PEG/rGO electrodes, showcasing their potential for high-performance supercapacitor applications.

Protonated C3N4 Nanosheets for Enhanced Energy Storage in Symmetric Supercapacitors through Hydrochloric Acid Treatment.

Next-generation electrochemical energy storage materials are essential in delivering high power for long periods of time. Double-layer carbonaceous materials provide high power density with low energy density due to surface-controlled adsorption. This limitation can be overcome by developing a low-cost, more abundant material that delivers high energy and power density. Herein, we develop layered C3N4 as a sustainable charge storage material for supercapacitor applications. It was thermally polymerized using urea and then protonated with various acids to enhance its charge storage contribution by activating more reaction sites through the exfoliation of the C-N framework. The increased electron-rich nitrogen moieties in the C-N framework material lead to better electrolytic ion impregnation into the electrode, resulting in a 7-fold increase in charge storage compared to the pristine material and other acids. It was found that C3N4 treated with hydrochloric acid showed a very high capacitance of 761 F g-1 at a current density of 20 A g-1 and maintained 100% cyclic retention over 10,000 cycles in a three-electrode configuration, outperforming both the pristine material and other acids. A symmetric device was fabricated using a KOH/LiI gel-based electrolyte, exhibiting a maximum specific capacitance of 175 F g-1 at a current density of 1 A g-1. Additionally, the device showed remarkable power and energy density, reaching 600 W kg-1 and 35 Wh kg-1, with an exceptional cyclic stability of 60% even after 5000 cycles. This study provides an archetype to understand the underlying mechanism of acid protonation and paves the way to a metal-carbon-free environment.

Enriched performance of practical device assisted asymmetric supercapacitor: NiO/Co3O4 intercalated with rGO nanocomposite electrodes

In this present report, we developed high performance supercapacitor electrode material of NiO/Co3O4/rGO ternary nanocomposites synthesized by a hydrothermal method with a different nickel and cobalt molar proportions. The phase formation, surface morphology and elemental information studies of binary NiO/Co3O4 and ternary NiO/Co3O4/rGO nanocomposites were investigated. The electrochemical investigations of the binary and ternary nanocomposites electrodes have been examined. Compare with various molar proportions, the ternary NiO/Co3O4(1,3)/rGO nanocomposites shows an extraordinary capacitance value of 980 Fg−1 at 1 Ag−1 as well as robust cycle life (cyclic retention of 92 % over the 5000 cycles at 10 Ag−1). In 0–1.4 V, an asymmetric supercapacitor attained a specific capacitance of 87.2 Fg−1 and large power density (1396.3 W/kg) with extreme energy density (23.7 Wh/kg). Moreover, assembled device reveals a great rate capability (89 % over the 5000 cycles in the electrolyte of PVA-KOH). The ternary electrode has high capacitance, capacitance retention and large energy density due to NiO and Co3O4 nanoparticles being intercalated with the high surface of rGO, as well as the synergetic effect of NiO/Co3O4 and rGO.

Recycling of protective layer of Ni rich layered oxide material in Li ion batteries

We investigated the recycling of protective layer of Ni rich layered oxide–material used in Li ion batteries. Decreasing electrochemical performance of the cathode powder while leaving the powder in air was confirmed by various analyses and was found to be due to the formation of lithium residuals. The surface of the protective layer of Ni rich layered oxide was covered by the lithium residuals and that led to the cancellation of the coating effect. The residual lithium decreased and the cell performance was recovered by following a recycling process in this work. After the recycling process, the performance of the protective layer became similar to that of the layer immediately after the initial coating, and the coating layer showed a resurgence, which was confirmed by SEM and TEM images. The capacity of the initial coated Ni rich NCM and the sample after recycling was 209 and 206 mAh/g at 1C, respectively. The cycle retention for the initial coated Ni rich NCM and the sample after recycling was 93.4 and 92.6 % after 50 cycles at 1C, respectively. It is concluded that the coating layer and the electrochemical performance were recovered by the recycling process.

Unraveling the reaction activity of Fe-based compounds toward potassium-ion storage

Iron-based compounds have been extensively applied as anode materials for alkali-ion batteries. Nevertheless, how the intrinsic properties of Fe-based compounds affect their alkali-ion storage behavior still remain blurry, hampering the rational structure design of Fe-based anodes for superior performance. Herein, the reaction activities of various Fe-based compounds (e.g., FeS2, FeSe2, and FeP) toward K/Na/Li-ion storage are studied by rationally encapsulating Fe-compounds into hollow carbon boxes with an identical multi-yolk-shell structure. For potassium storage, FeSe2@C composite manifests the best battery performance with high capacity, superior rate capability, and excellent cycling behavior. FeS2@C exhibits high capacity, but with poor cycling retention and inferior rate capability. FeP@C shows the lowest capacity and poorest rate capability. As disclosed by density functional theory calculation and kinetics analysis, the superior potassium storage behavior of FeSe2@C is due to the high electrical conductivity and proper K+ diffusion ability of FeSe2, as well as its excellent pseudocapacitive behavior. The weak electron conductivity of FeS2 is responsible for its poor rate performance, and the large K+ diffusion barrier of FeP leads to its low reaction activity toward potassium-ion storage. Moreover, FeSe2@C also displays best rate capability among these Fe-based composites for both sodium and lithium storage.

Na3V2(PO4)3 Cathode for Room-Temperature Solid-State Sodium-Ion Batteries: Advanced In Situ Synchrotron X-ray Studies to Understand Intermediate Phase Evolution.

Sodium-ion batteries (NIBs) can use elements that are abundantly present in Earth's crust and are technologically feasible for replacing lithium-ion batteries (LIBs). Hence, NIBs are essential components for sustainable energy storage applications. All-solid-state sodium batteries are among the most capable substitutes to LIBs because of their potential to have low price, great energy density, and consistent safety. Nevertheless, more advancements are needed to improve the electrochemical performance of the Na3V2(PO4)3 (NVP) cathode for NIBs, especially with regard to rate performance and operational lifespan. Herein, a core-shell NVP/C structure is accomplished by adopting a solid-state method. The initial reversible capacity of the NVP/C cathode is 106.6 mAh/g (current rate of C/10), which approaches the theoretical value (117.6 mAh/g). It also exhibits outstanding electrochemical characteristics with a reversible capacity of 85.3 mAh/g at 10C and a cyclic retention of roughly 94.2% after 1100 cycles. Using synchrotron-based operando X-ray diffraction, we present a complete examination of phase transitions during sodium extraction and intercalation in NVP/C. To improve safety and given its excellent ionic conductivity and broad electrochemical window, a Na superionic conductor (NASICON) solid electrolyte (Na3.16Zr1.84Y0.16Si2PO12) has been integrated to obtain an all-solid-state NVP/C||Na battery, which provides an exceptional reversible capacity (95 mAh/g at C/10) and long-term cycling stability (retention of 78.3% after 1100 cycles).

A Study on Long-Term Cycling Performance by External Pressure Change for Pouch-Type Lithium Metal Batteries

<p>Lithium dendrite formation is one of the most significant problems with lithium metal batteries. The lithium dendrite reduces the lithium metal batteries’ cycling life and safety. To apply consistent external pressure to a lithium metal pouch cell, we design a press jig in this study. External pressure creates dense lithium morphology by preventing lithium dendrite formation. After 300 cycles at 1 C, the cells with the external pressure perform far better than the cells without it, with a cycling retention of 97.8%. The formation of stable lithium metal is made possible by external pressure, which also enhances safety and cyclability.</p>

Characterization of an In-Situ Soil Organic Carbon (SOC) via a Smart-Electrochemical Sensing Approach.

Soil is a vital component of the ecosystem that drives the holistic homeostasis of the environment. Directly, soil quality and health by means of sufficient levels of soil nutrients are required for sustainable agricultural practices for ideal crop yield. Among these groups of nutrients, soil carbon is a factor which has a dominating effect on greenhouse carbon phenomena and thereby the climate change rate and its influence on the planet. It influences the fertility of soil and other conditions like enriched nutrient cycling and water retention that forms the basis for modern 'regenerative agriculture'. Implementation of soil sensors would be fundamentally beneficial to characterize the soil parameters in a local as well as global environmental impact standpoint, and electrochemistry as a transduction mode is very apt due to its feasibility and ease of applicability. Organic Matter present in soil (SOM) changes the electroanalytical behavior of moieties present that are carbon-derived. Hence, an electrochemical-based 'bottom-up' approach is evaluated in this study to track soil organic carbon (SOC). As part of this setup, soil as a solid-phase electrolyte as in a standard electrochemical cell and electrode probes functionalized with correlated ionic species on top of the metalized electrodes are utilized. The surficial interface is biased using a square pulsed charge, thereby studying the effect of the polar current as a function of the SOC profile. The sensor formulation composite used is such that materials have higher capacity to interact with organic carbon pools in soil. The proposed sensor platform is then compared against the standard combustion method for SOC analysis and its merit is evaluated as a potential in situ, on-demand electrochemical soil analysis platform.

High Volumetric Energy Density LiFePO4/C Cathode Materials Synthesized by Dodecyl Polyglucoside-Assisted Glucose-Polyethylene Glycol Composite Carbon Source

Abstract High volumetric energy density LiFePO4/C cathode materials were synthesized by wet ball milling, spray drying, and carbothermal reduction method using glucose and polyethylene glycol (PEG) as composite carbon sources and dodecyl polyglucoside (C12APG) as a milling aid. With the introduction of C12APG during the ball milling process, the prepared cathode materials have uniform particle size (100-200 nm in diameter) and regular primary particle morphology. In addition, PEG substitutes part of glucose as a carbon source, resulting in low carbon content and high graphitization of residual carbon after high-temperature calcination. The prepared LiFePO4/C cathode materials have a high powder compaction density (2.68 g cm-3) and excellent electrochemical performance (discharged capacities of 161.2 and 141.7 mAh g-1 at 0.2 C and 5 C, and cycle retention of 98.6% for 100 cycles at 1 C/1 C). This LiFePO4/C composite was assembled into 14500-type cylindrical batteries with a compaction density of 2.62 g cm-3 for the positive electrode. The volumetric energy densities of the positive electrode were 1135.18 Wh L-1 and 918.16 Wh L-1 at 0.2 C and 5 C, respectively.

Introducing an Efficient and Eco-Friendly Spray-Drying Process for the Synthesis of NCM Precursor for Lithium-ion Batteries

<p>Ni-rich cathode is one of the promising candidates for high-energy lithium-ion battery applications. Due to its specific capacity, easy industrialization, and good circulation ability, Ni-rich cathode materials have been widely used for lithium-ion batteries. However, due to the limitation of the co-precipitation method, including sewage pollution, and the instability of the long production cycles, developing a new efficient and environmentally friendly synthetic approach is critical. In this study, the Ni<sub>0.91</sub>Co<sub>0.06</sub>Mn<sub>0.03</sub>CO<sub>3</sub> precursor powder was successfully synthesized by an efficient spray-drying method using carbonate compounds as a raw material. This Ni<sub>0.91</sub>Co<sub>0.06</sub>Mn<sub>0.03</sub>CO<sub>3</sub> precursor was calcined by mixing with LiOH·H<sub>2</sub>O (5 wt% excess) at 480°C for 5 hours and then sintered at two different temperatures (780°C/800°C) for 15 hours under an oxygen atmosphere to complete the cathode active material preparation, which is a key component of lithium-ion batteries. As a result, LiNi<sub>0.91</sub>Co<sub>0.06</sub>Mn<sub>0.03</sub>O<sub>2</sub> cathode active material powders were obtained successfully via a simple sintering process on the Ni<sub>0.91</sub>Co<sub>0.06</sub>Mn<sub>0.03</sub>CO<sub>3</sub> precursor powder. Furthermore, the obtained LiNi<sub>0.91</sub>Co<sub>0.06</sub>Mn<sub>0.03</sub>O<sub>2</sub> cathode active material powders were characterized. Overall, the material sintered at 780°C shows superior electrochemical performance by delivering a discharge capacity of 190.76mAh/g at 1<sup>st</sup> cycle (0.1 C) and excellent capacity retention of 66.80% even after 50 cycles.</p>

Effect of Film Density on MgSiO3-Based Resistive Random-Access Memory

Different film density MgSiO3 based resistive random-access memorys (RRAMs) are fabricated to investigate the resistive switching behaviors. The X-ray diffraction results, set voltage, reset voltage, cycling endurance, and retention time are drawn for comparison. With the increasing oxygen ratio gas flow, the resistive switching characteristics of MgSiO3 RRAM are drastically elevated by changing the fabrication conditions of the RS layer. Moreover, we portray a filament model to explain the most likely mechanism associated with the generation and rupture of conductive filaments composed of oxygen vacancies. The high randomness among switching cycles for memory application should be prevented, but it is suitable for the physical unclonable function. The relationship between HRS and the next time set voltage shows a strong correlation, and the conduction mechanisms of the low-resistance state (LRS) and HRS correspond to ohmic conduction and space charge-limited conduction, respectively. Meanwhile, the RRAM undergoes 10,000 s retention tests, and the two resistance states can be distinguished without obvious alternation or degradation. A favorable cycling endurance and retention time achieved by optimizing the fabrication parameters of Cu/MgSiO3/Pt RRAM have the potential for nonvolatile memristors and information security applications.

Novel hierarchical core-shell NiCo2S4@NiWO4 nanowire arrays for high performance pseudocapacitor

In this paper, a novel NiCo2S4@NiWO4 honeycomb core-shell nanorod array significantly improved the electrochemical storage properties of supercapacitors. The characteristic architecture of the NiCo2S4@NiWO4 electrode showed a remarkable specific capacity of 1273.5 C g−1 at a current density of 1 A g−1. The asymmetric supercapacitor (ACS) had a high specific capacitance of 1502.4 C g−1 at a current density of 1 A g−1 as well as excellent cycling stability at a current density of 10 A g−1 (101.25 % cycling retention rate after 10,000 cycles), and an energy density of 334 Wh kg−1 with a power density of 2.38 kW kg−1. The research emphasized that a strong electronic coupling effect was observed at the interface of NiCo2S4 and NiWO4 and electron transfer from Ni-W-O to Ni-Co-S occurred around the interface, which further improved the electron transfer properties of electrode materials and hit the mark extends the life of the electrode and significantly improves the performance of energy storage systems.