Mass Of Active Materials Research Articles

Silicon nanowire growth on carbon cloth for flexible Li-ion battery anodes

Binder and conductive additive-free Si nanowires (NWs) grown directly on the current collector have shown great potential as next generation Li-ion battery anodes. However, low active material mass loadings and consequentially low areal capacities have remained a challenge in their development. Herein, we report the high-density growth of Si NWs on carbon cloth (CC) for use as Li-ion battery anodes. The NW growth reactions were carried out using a modified, glassware-based solvent vapor growth (SVG) process. Optimized growth conditions were applied to CC substrates to generate flexible Si NW anodes for Li-ion batteries. Battery testing revealed high areal charge and discharge capacities (>2 mAh/cm2) compared to Si NWs grown on stainless steel (SS) substrates (∼0.3 mAh/cm2) and stable long-term cycling with 80% capacity retention after 200 cycles. The findings reported herein represent a significant advancement in the field in terms of achievable areal capacity enabled by a low-cost glassware-based system.

Evaporation-induced hydrated graphene/polyaniline/carbon cloth integration towards high mass loading supercapacitor electrodes

The convenient fabrication of supercapacitor electrodes with high active material mass loading is of great significance to the practical application. In this paper, a novel and efficient strategy is proposed to prepare graphene/polyaniline (PANI) composite with controllable mass loading towards high-performance supercapacitor electrodes. The graphene oxide (GO)/PANI colloid layer is drop-coated onto carbon cloth (CC) before evaporating most of the water. The as-obtained hydrated GO/PANI/CC film undergoes a facile hydrazine reduction treatment and yields the porous reduced GO (rGO)/PANI active layer fixed on the CC current collector, which could directly act as the binder-free supercapacitor electrode. As a result, the excellent adhesion of active layer with CC and the uniform PANI distribution on porous rGO matrix contribute greatly to the fast electron and ion transport in the electrochemical activities. The integrated rGO/PANI/CC electrode achieves a high specific capacitance of 871.5 F g−1 at the current density of 1.5 A g−1 with superior rate performance. More importantly, repeating the drop-coating/water-evaporating process could conveniently realize the high rGO/PANI mass loading (up to 10 mg cm−2) on the current collector. The corresponding symmetric all-solid-state supercapacitors with different mass loadings can deliver the maximum energy densities of 39.1 Wh kg−1, 425.3 μWh cm−2, and 4.0 mWh cm−3, manifesting their promising practical prospect. This work would provide a new path for the fabrication of graphene-based supercapacitor electrodes and other functional film materials.

Production of fast-charge Zn-based aqueous batteries via interfacial adsorption of ion-oligomer complexes.

Aqueous zinc batteries are attracting interest because of their potential for cost-effective and safe electricity storage. However, metallic zinc exhibits only moderate reversibility in aqueous electrolytes. To circumvent this issue, we study aqueous Zn batteries able to form nanometric interphases at the Zn metal/liquid electrolyte interface, composed of an ion-oligomer complex. In Zn||Zn symmetric cell studies, we report highly reversible cycling at high current densities and capacities (e.g., 160 mA cm−2; 2.6 mAh cm−2). By means of quartz-crystal microbalance, nuclear magnetic resonance, and voltammetry measurements we show that the interphase film exists in a dynamic equilibrium with oligomers dissolved in the electrolyte. The interphase strategy is applied to aqueous Zn||I2 and Zn||MnO2 cells that are charged/discharged for 12,000 cycles and 1000 cycles, respectively, at a current density of 160 mA cm−2 and capacity of approximately 0.85 mAh cm−2. Finally, we demonstrate that Zn||I2-carbon pouch cells (9 cm2 area) cycle stably and deliver a specific energy of 151 Wh/kg (based on the total mass of active materials in the electrode) at a charge current density of 56 mA cm−2.

Overcharge to Remove Cathode Passivation Layer for Reviving Failed Li–O 2 Batteries

Overcharge to Remove Cathode Passivation Layer for Reviving Failed Li–O ₂ Batteries

All-Electrochemical Nanofabrication of Stacked Ternary Metal Sulfide/Graphene Electrodes for High-Performance Alkaline Batteries.

Energy-storage materials can be assembled directly on the electrodes of a battery using electrochemical methods, this allowing sequential deposition, high structural control, and low cost. Here, a two-step approach combining electrophoretic deposition (EPD) and cathodic electrodeposition (CED) is demonstrated to fabricate multilayer hierarchical electrodes of reduced graphene oxide (rGO) and mixed transition metal sulfides (NiCoMnSx ). The process is performed directly on conductive electrodes applying a small electric bias to electro-deposit rGO and NiCoMnSx in alternated cycles, yielding an ideal porous network and a continuous path for transport of ions and electrons. A fully rechargeable alkaline battery (RAB) assembled with such electrodes gives maximum energy density of 97.2 Wh kg-1 and maximum power density of 3.1 kW kg-1 , calculated on the total mass of active materials, and outstanding cycling stability (retention 72% after 7000 charge/discharge cycles at 10 A g-1 ). When the total electrode mass of the cell is considered, the authors achieve an unprecedented gravimetric energy density of 68.5 Wh kg-1 , sevenfold higher than that of typical commercial supercapacitors, higher than that of Ni/Cd or lead-acid Batteries and similar to Ni-MH Batteries. The approach can be used to assemble multilayer composite structures on arbitrary electrode shapes.

Architecting a 3D continuous C/CuVO3@Cu composite anode for lithium-ion storage

Vanadium (V)-based oxides with a high theoretical capacity are an alternative anode for lithium-ion (Li+) batteries, but they are still limited by the poor conductivity, large volume change and low active material mass loading. Herein, a three-dimensional (3D) continuous C/CuVO3@Cu composite anode with high copper (II) metavanadate (IV) (CuVO3) mass loading is synthesized by the combination of high-energy ball milling, non-solvent-induced phase separation and heat treatment. The copper (Cu) framework can enhance electron/ion conductivity in coordination with amorphous carbon (C). Furthermore, the macropore channels in the copper framework can provide buffer space for the volume expansion of active material copper (II) metavanadate (IV) during lithiation/delithiation. As a result, this 3D continuous C/CuVO3@Cu composite anode achieves a high copper (II) metavanadate (IV) mass loading of about 3.8 mg/cm2, delivering a reversible capacity of 479 mAh/g at 100 mA/g after 120 cycles. More importantly, a long life span is achieved with a reversible capacity of 268 mAh/g even after 1700 cycles at a high current density of 1000 mA/g, demonstrating excellent cycle performance. This work provides a way to develop 3D continuous composite material anodes with extraordinary electrochemistry performance for next-generation energy-storage devices.

Magnesiothermic reduction improved route to high-yield synthesis of interconnected porous Si@C networks anode of lithium ions batteries

Silicon (Si) based materials has been envisaged as a promising anode material for the next-generation high energy-density lithium-ion batteries (LIBs) thanks to its ultrahigh specific capacity. The development of reliable Si anode yet faces challenges of how to explore a simple, convenient and controllable synthetic route of Si composite anode with high conductivity and favorable structure. Herein, we report a newly synthetic route by extending the well-known Mg-thermal reduction method for the high-yield fabrication of three-dimensional (3D) porous Si/C nano-architectures (p-Si@C) featuring interconnected conductive networks and hierarchical mesoporous structure, endowing it with favorable properties and structure as anode of lithium-ions batteries (LIBs). Comprehensive characterization via various techniques coupling with density functional theory calculations demonstrates the as-prepared p-Si@C nano-architectures are favorable for forming stable solid-electrolyte interface (SEI), facilitating Li+ transport and electrons transfer, and mitigating the volume expansion effect upon for Li+ storage. As such, the Si@C nano-architectures not only exhibit high reversible capacity of 1078.68 mAh g−1 and impressively high cycling stability over 500 cycles at 1 A g−1 but also keep a quite attractive capacity retention rate of 47.9% even increasing rate to 10 A g−1. The feasibility of its practical application has been demonstrated by a lithium-ion full battery with the commercial lithium iron phosphate (LFP) as cathode, which delivers a stable reversible capacity of 124.4 mA g−1 and boasting high energy density of 381.61 Wh kg−1 at 0.2 C based on total mass of active material of the cathode and anode.

Conversion-type fluoride cathodes: Current state of the art

Conversion-type transition metal fluoride cathodes offer a 200%–300% higher theoretical energy density limit than state-of-the-art intercalation cathodes. Recent publications have reshaped our understanding of the reaction mechanism in these materials. Herein, we review recent reports highlighting how active material dissolution, particle fusing, electrolyte consumption, and the resultant capacity fade can be mitigated by rational electrolyte design. Recent work has established the possibility of high discharge rate in transition metal fluorides at significant active material mass fraction; we examine the relationship between rate capability and active material fraction. Tuning transition metal fluoride chemistry via cation and anion substitution has demonstrated the potential to improve its electrochemical properties. A brief technoeconomic analysis is presented to highlight the practical advantages of different transition metal chemistries.

Feature Analyses and Modeling of Lithium-Ion Battery Manufacturing Based on Random Forest Classification

Lithium-ion battery manufacturing is a highly complicated process with strongly coupled feature interdependencies; a feasible solution that can analyze feature variables within manufacturing chain and achieve reliable classification is, thus, urgently needed. This article proposes a random forest (RF)-based classification framework, through using the out of bag predictions, Gini changes, as well as predictive measure of association (PMOA), for effectively quantifying the importance and correlations of battery manufacturing features and their effects on the classification of electrode properties. Battery manufacturing data containing three intermediate product features from the mixing stage and one product parameter from the coating stage are analyzed by the designed RF framework to investigate their effects on both the battery electrode active material mass load and porosity. Illustrative results demonstrate that the proposed RF framework not only achieves the reliable classification of electrode properties, but also leads to the effective quantification of both manufacturing feature importance (FI) and correlations. This is the first time to design a systematic RF framework for simultaneously quantifying battery production FI and correlations by three various quantitative indicators, including the unbiased FI, gain improvement FI, and PMOA, paving a promising solution to reduce model dimension and conduct efficient sensitivity analysis of battery manufacturing.

Bismuth nanorods confined in hollow carbon structures for high performance sodium- and potassium-ion batteries

Bismuth has drawn widespread attention as a prospective alloying-type anode for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to its large volumetric capacity. However, such material encounters drastic particle pulverization and overgrowth of solid-electrolyte interphase (SEI) upon repeated (de)alloying, thus causing poor rate and cycling degradation. Herein, we report a unique structure design with bismuth nanorods confined in hollow N, S-codoped carbon nanotubes (Bi@NS-C) fabricated by a solvothermal method and in-situ thermal reduction. Ex-situ SEM observations confirm that such a design can significantly suppress the size fining of Bi nanorods, thus inhibiting the particle pulverization and repeated SEI growth upon charging/discharging. The as achieved Bi@NS-C demonstrates outstanding rate capability for SIBs (96.5% capacity retention at 30 A g−1 vs. 1 A g−1), and a record high rate performance for PIBs (399.5 mAh g−1 @ 20 A g−1). Notably, the as constructed full cell (Na3V2(PO4)3@C|Bi@NS-C) demonstrates impressive performance with a high energy density of 219.8 W h kg−1 and a high-power density of 6443.3 W kg−1 (based on the total mass of active materials on both electrodes), outperforming the state-of-the-art literature.

Direct Ink Printing for Flexible Zinc‐Ion‐Hybrid Micro‐Supercapacitors Based on Hierarchical Porous Carbon as Cathode

AbstractFlexible artificial intelligence and rechargeable electronic devices have been the research hotpot due to the status quo of the energy crisis. However, the existing energy storage devices suffering from undesirable electrochemical performance, poor flexibility, and toxicity, have unsatisfactory practical application prospect. Owing to its unique stability, normal electrodes in energy storage equipment are built out of carbon‐based materials. Recently, zinc hybrid supercapacitors have attracted a lot of attention. Herein, a high‐performance zinc‐ion hybrid micro‐supercapacitor is successfully constructed using hierarchical honeymoon‐like porous carbon frameworks as cathode by direct ink printing method. Due to the bivalent feature of zinc and electric double layered capacitive characteristic of the porous carbon, the optimized device possesses excellent electrochemical performance of excellent specific capacity of 189.06 mA h g−1 at a current density of 1 mA cm−2, high energy density of76.38 Wh kg−1, power density of 499.94 W kg−1 and superior capacity retention of 95.71 % at 10 mA cm−2 after 1000 cycles. Through direct ink printing, the as‐assembled zinc hybrid micro‐supercapacitors based on flexible substrate exhibit outstanding flexibility with controllable active material mass loading.

Особенности проектирования турбогенератора с повышенной частотой вращения 6000 об/мин

Object and purpose of research. The object under study is a 36 МW turbo-alternator (TA) with electromagnetic excitation and a high rotational speed of 6000 rpm, which can be used as an option for ac electric power source of 100 Hz in ship electric power systems with a turbo-alternator plant. The purpose is to perform electromagnetic calculations to determine TA main data and technical characteristics, including the stator and rotor pack, their design, mass of active materials, etc. for comparison with a TA of the same power but 3000 rpm. Materials and methods. The studies are based on research and engineering data about investigations and design of double-pole industrial TA of 50 Hz as well as TA with a high current frequency (100 Hz and higher). For this purpose, the known formulas were used to estimate the size of TA active elements, excitation forces of stator and rotor windings, as well as methods for calculation of main TA parameters and technical characteristics. Main results. Design specifics of TA with a high rotational speed of 6000 rpm is identified, and results of electromagnetic estimations are obtained for a specific 36 MW turbo-alternator of 100 Hz with a forced close cycle cooling and better mass and size characteristics. Conclusions. The obtained results are of practical value, showing feasibility of developing a version of 36.0 МW TA with a rotational speed of 6000 rpm and significantly reduced specific mass and size characteristics – tentatively by 35–40 % as compared to the existing TA of the same power but with a speed of 3000 rpm.

Gelatin-derived honeycomb like porous carbon for high mass loading supercapacitors

Using gelatin as the carbon source and glutaraldehyde as the cross linking agent, a novel honeycomb like porous carbon has been successfully prepared through simple cross linking reaction and KOH activation at high temperature. Compact and uniform honeycomb morphology has been formed in Gel/G-1.0 (Gel represents gelatin, G represents glutaraldehyde, and 1.0 represents the amount of glutaraldehyde) which brings micropores and high specific surface area (SSA). Heteroatoms including O and N have been introduced into carbon material which contribute pseudo-capacitance. Higher degree of graphitization for Gel/G-1.0 has improved the conductivity of the carbon material which exhibits good electrochemical performances under high mass loading. When the active carbon material mass loading is about 10 mg, the specific capacitance (Csp) of Gel/G-1.0 is 392 F g−1 at current density of 1 A g−1 in 2 M H2SO4, with high retention of 64% at current density of 10 A g−1. More importantly, the carbon material exhibits a high energy density of 6.39 W h kg−1 with the power density of 50.03 W kg−1, even at the power density of 502.79 W kg−1, the energy density remains 5.00 W h kg−1. This simple synthesis strategy and outstanding electrochemical performances of carbon materials with high mass loading are great significance in the application of supercapacitors.

Multi-shelled bimetal V-doped Co3O4 hollow spheres derived from metal organic framework for high performance supercapacitors

Using hollow structures containing more than one transition metal oxide seems to be essential to respond to the new generation of energy storage electrodes with remarkable performance for advanced expansions of new electronic devices. In this work, facile and controllable synthesis of multi-shelled V-doped Co3O4 hollow spheres derived from metal-organic framework through a solvothermal process followed by annealing as heat treatment has been studied. A comprehensive investigation of the hollow spheres in case of morphological, structural, and electrochemical behavior has been carried out. The multi-shelled V-doped Co3O4 (MS-V-CO) electrode displays well results, including electrochemical behavior (little internal resistance, fast kinetics, great reversibility, an excellent specific capacitance of 1593 F g−1), and structural features (high surface area (61.4 m2 g−1), multi shell structure, and wrinkled surface). An asymmetric supercapacitor (ASC) device has been assembled using multi shell vanadium doped cobalt oxide as the positive electrode (anode) and activated carbon (AC) as the negative electrode (cathode) and investigated for electrochemical performance. MS-V-CO//AC shows good behavior with a maximum energy density of 66.88 Wh kg−1 and power density of 240 Wkg−1 at 0.3 A g−1, relying on the total mass of active materials on both electrodes.

Modeling Current Density Non-Uniformity to Detect Premature Failure in 3D Lithium-Ion Batteries

Conventional Lithium-ion (Li-ion) intercalation batteries that are composed of planar cathode, separator, and anode layers bear an intrinsic trade-off between energy density and power density. While thick electrodes allow for more active material loading and higher energy densities, thick electrodes lengthen ion transport pathways and limit power and fast charging performance. Conversely, thin electrodes have fast ion transport at the cost of reduced material loading which leads to lower energy densities. Due to the high weight and volume ratio of inactive components, stacking layers of thin planar batteries is inefficient for high capacity cells.1 Three-dimensional (3D) batteries decouple the power-energy trade-off in planar batteries by modifying electrode architecture on a micron to millimeter scale.2 3D batteries redistribute electrode material beyond planar geometry to controlled 3D spatial arrangements in pursuance of shorter ion-transport pathways and enhanced fast charging behavior in a battery cell. This enables high power performance without sacrificing the mass of active material in the cell, and ideally maintains high energy and power performance at high discharge and charge rates. However, a known issue in 3D batteries is the inhomogeneous transport distances between electrodes leading to nonuniform current density and local depletion of the electrode or electrolyte material.3,4 These nonuniformities can terminate a discharge or charge cycle prematurely. Although many 3D batteries have been proposed to date, few comparative modeling studies have been conducted for these architectures to understand their relative performance gains.In this work, we adapt a two-dimensional current density uniformity index (UI) measure from previous work5 and investigate its usage as a potential 3D metric for quantifying premature failure in 3D batteries. A series of 3D batteries are simulated using the software AMPERES that models a 3D electrochemical systems at the continuum level using volume-averaging techniques.6 Two material models – LiFePO4 (LFP) | Li4Ti5O12 (LTO) and LiNi0.5Mn0.3Co0.2O2 (NMC532) | Graphite – are investigated for each 3D battery architecture. We also visualize 3D Li-ion concentration profiles and Li-ion transport pathways to qualitatively analyze the transport behavior in each 3D battery. Our results show that 3D battery performance is material dependent, and 3D batteries with premature depletion demonstrate high UI metrics early in a discharge cycle. References C. L. Cobb and S. E. Solberg, J. Electrochem. Soc., 164, A1339–A1341 (2017).C. L. Cobb and M. Blanco, Journal of Power Sources, 249, 357–366 (2014).R. Hart, H. White, B. Dunn, and D. Rolison, Electrochemistry Communications, 5, 120–123 (2003).A. A. Talin, D. Ruzmetov, A. Kolmakov, K. McKelvey, N. Ware, F. El Gabaly, B. Dunn, and H. S. White, ACS Appl. Mater. Interfaces, 8, 32385–32391 (2016).D. Grazioli, V. Zadin, D. Brandell, and A. Simone, Electrochimica Acta, 296, 1142–1162 (2019).S. Allu, S. Kalnaus, S. Simunovic, J. Nanda, J.A. Turner, and S. Pannala, Journal of Power Sources, 325, 42–50 (2016). Acknowledgements This work was funded in part by a Defense Advanced Research Projects Agency (DARPA) Young Faculty Award under grant number D19AP00038. The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government.

(Invited) Optimization of Highly Ordered Laser-Patterned Electrode (HOLE) Design for Achieving Enhanced Fast Charging Performance in Graphite Anodes with > 3mAh/cm2 loading

For widespread adoption of electric vehicles, we need Li-ion batteries (LIBs) that are both energy and power dense. In the state-of-art Li-ion batteries, there exists a tradeoff between the energy and power density. This tradeoff originates due to the electrode design used in conventional LIBs, where one needs to increase the loading of active material (either in terms of active material mass fraction or the electrode thickness) to achieve high energy density. However, such a design limits the mass transport of electrolyte, which leads to it poor performance at high-charging rates. It has been demonstrated that the rate performance of the energy dense electrodes can be improved by employing 3D architectures such as highly ordered laser-patterned electrode (HOLE),1 which alleviate the electrolyte mass transport limitations by providing rapid mass transport via laser ablated channels through the electrode thickness. In this study, we investigate how the geometric parameters of the HOLE design such as inter-channel spacing and channel radius affect the fast-charging performance of graphite anodes with > 3 mAh/cm2 loading and the HOLE architecture. We conduct this analysis using a fully parameterized continuum scale model based on the porous electrode theory. Our results show that for a constant volume retained (after the laser ablation), the smaller and closer channels exhibit better 4C charging performance than the channels that are larger and farther. The improved performance of a HOLE anode with smaller and closer channels is a result of the small value of the Damköhler number, Da, defined as the ratio between the characteristic diffusion time and reaction time, for the anode. Furthermore, we developed a semi-analytical framework to estimate Da for a given HOLE design, which includes the channel spacing, size, and arrangement. The results from the analysis match closely with the results from the 3D simulations. Thus, our framework can be used for optimization architectures similar to the HOLE architectures without the need of running computationally expensive 3D simulations. In addition to our simulation results, we will also discuss the automated process that was developed to parameterize our model.

Machine learning for optimised and clean Li-ion battery manufacturing: Revealing the dependency between electrode and cell characteristics

The large number of parameters involved in each step of Li-ion electrode manufacturing process as well as the complex electrochemical interactions in those affect the properties of the final product. Optimization of the manufacturing process, although very challenging, is critical for reducing the production time, cost, and carbon footprint. Data-driven models offer a solution for manufacturing optimization problems and underpin future aspirations for manufacturing volumes. This study combines machine-learning approaches with the experimental data to build data-driven models for predicting final battery performance. The models capture the interdependencies between the key parameters of electrode manufacturing, its structural features, and the electrical performance characteristics of the associated Li-ion cells. The methodology here is based on a set of designed experiments conducted in a controlled environment, altering electrode coating control parameters of comma bar gap, line speed and coating ratio, obtaining the electrode structural properties of active material mass loading, thickness, and porosity, extracting the manufactured half-cell characteristics at various cycling conditions, and finally building models for interconnectivity studies and predictions. Investigating and quantifying performance predictability through a systems' view of the manufacturing process is the main novelty of this paper. Comparisons between different machine-learning models, analysis of models’ performance with a limited number of inputs, analysis of robustness to measurement noise and data-size are other contributions of this study. The results suggest that, given manufacturing parameters, the coated electrode properties and cell characteristics can be predicted with about 5% and 3% errors respectively. The presented concepts are believed to link the manufacturing at lab-scale to the pilot-line scale and support smart, optimised, and clean production of electrodes for high-quality Li-ion batteries.

Battery Electrode Mass Loading Prognostics and Analysis for Lithium-Ion Battery–Based Energy Storage Systems

With the rapid development of renewable energy, the lithium-ion battery has become one of the most important sources to store energy for many applications such as electrical vehicles and smart grids. As battery performance would be highly and directly affected by its electrode manufacturing process, it is vital to design an effective solution for achieving accurate battery electrode mass loading prognostics at early manufacturing stages and analyzing the effects of manufacturing parameters of interest. To achieve this, this study proposes a hybrid data analysis solution, which integrates the kernel-based support vector machine (SVM) regression model and the linear model–based local interpretable model-agnostic explanation (LIME), to predict battery electrode mass loading and quantify the effects of four manufacturing parameters from mixing and coating stages of the battery manufacturing chain. Illustrative results demonstrate that the derived hybrid data analysis solution is capable of not only providing satisfactory battery electrode mass loading prognostics with over a 0.98 R-squared value but also effectively quantifying the effects of four key parameters (active material mass content, solid-to-liquid ratio, viscosity, and comma-gap) on determining battery electrode properties. Due to the merits of explainability and data-driven nature, the design data–driven solution could assist engineers to obtain battery electrode information at early production cases and understand strongly coupled parameters for producing batteries, further benefiting the improvement of battery performance for wider energy storage applications.

Foldable high‐strength electrode enabled by nanosheet subunits for advanced sodium‐ion batteries

AbstractPower sources with strong mechanical properties and high‐energy density are highly desirable for the next‐generation flexible electronics. However, the challenge arises from the current electrode structure design, which is unable to bring both satisfactory mechanical and electrochemical properties with high active materials content and mass. Herein, we reported novel flexible, high‐strength, and mechanically stable TiO2‐based film electrodes for advanced sodium‐ion batteries, achieving an ultrahigh strength (up to ≈60 MPa) and commercial‐level areal capacity (4.5 mAh cm−2). Highly‐dispersed TiO2 and interlaced carbon nanotube (CNT) networks are embedded in the sheet‐liked cellulose to form porous, high‐conductive, and high‐active TiO2‐C nanosheets that is basic building subunits of TiO2‐C films, allowing the films with structural robustness and origami‐level flexibility. This strategy reconciles the contradiction between mechanical properties and active material content in flexible electrodes, and the fabricated electrode with a high TiO2 content of >65% can be bent more than 11 000 times without breaking. Meanwhile, good capacity and excellent cycle stability (0.02‰ capacity‐decay rate over 9000 cycles) of TiO2‐C film under a higher active content (75%) has well satisfied the demands of flexible energy storage devices for electrochemical performances. This TiO2‐C subunit assembly methodology demonstrates enormous potential in high‐strength/toughness flexible electrode construction for flexible electronics.image

Катодный материал на основе LiNi1/3Mn1/3Co1/3O2 и активированного угля для гибридных накопителей энергии

The structure and specific electrochemical characteristics of a mixed cathode material based on ground LiNi1/3Mn1/3Co1/3O2 (NMC111) and highly porous activated carbon YEC-8B were studied. The mixed material containing 35 wt. % NMC111 and 65 wt. % YEC-8B (based on the mass of active materials), has a specific capacity ∼70% higher in comparison with the cathode material based on pure coal YEC-8B. It was shown that while cycling a lithium-ion supercapacitor with a cathode based on this mixed material at high current densities, no significant changes took place in the electrochemical characteristics of the material. It was demonstrated that this type of cathode material has two advantages: at low current densities it displays the charge-discharge properties of the cathode material of a lithium-ion battery with high specific energy, and at high current densities, it functions as a material of a supercapacitor with high specific power.