batterydata/paper-abstracts huggingface dataset:
For double-layer capacitors in alkaline electrolyte, the specific capacitance of the positive electrode is not equal to that of the negative one. Thus, capacitor performance cannot be optimal with a positive/negative electrode matching ratio of 1. In this study nanoporous glassy carbons (NPGCs) were employed as the electrodes of capacitors, and the influence of matching ratio between positive and negative electrode on capacitor performance was systematically investigated. In aqueous KOH, the specific capacitance of the positive electrode is lower than that of the negative electrode. The matching ratio at which a maximum capacitance is obtained is dependent on the values of the positive and negative electrode capacitance. At low current rate, the highest specific capacitance is achieved at a matching ratio slightly higher than 1. At high current rate, a capacitor has the highest specific capacitance with the lowest resistance at a matching ratio of 1.5. This indicates that an optimum matching relationship between positive and negative electrodes is attained.
Lithium–sulfur (Li–S) batteries have been considered as a prospective candidate of secondary high-energy storage systems, but the shuttle effect of polysulfides through separator is a vital challenge for battery development. Herein, we report a facile strategy to modify commercial polypropylene (PP) separator by depositing a laminar MXene-Nafion composite. Nafion, as a surfactant, results in an ordered layer-by-layer deposition of MXene sheets by filtration. By comparing this modification layer to references composed of Nafion and MXene, we demonstrate that the physical resistance of MXene and electrostatic repulsion of Nafion can synergistically inhibit the shuttle effect. And the resultant Li–S cell shows exceptional cycling stability: ultralow capacity decay of 0.03% per cycle over 1000 cycles at 1C. Furthermore, MXene promotes the re-utilization of polysulfides due to its electrical conduction, while Nafion in interlayer effectively transports Li+. Thus, the cell achieves highly enhanced initial capacity (1234 vs. 834 mAh g−1 for PP cell). Besides, these results are also much higher than that of a dual-layer modification layer (MXene@Nafion), highlighting the full synergism of organic and inorganic components in this laminar nanostructure. Moreover, the laminar GO-Nafion as an example verifies the universality of this design strategy.
This work proposes and analyzes a structurally-integrated lithium-ion battery concept. The multifunctional energy storage composite (MESC) structures developed here encapsulate lithium-ion battery materials inside high-strength carbon-fiber composites and use interlocking polymer rivets to stabilize the electrode layer stack mechanically. These rivets enable load transfer between battery layers, allowing them to store electrical energy while also contributing to the structural load carrying performance, without any modifications to the battery chemistry. The design rationale, fabrication processes, and experimental mechano-electrical characterization of first-generation MESCs are discussed. Experimental results indicate that the MESCs offer electrochemical performance comparable to standard lithium-ion cells, despite the disruptive design change. The mechanical performance of MESCs is assessed via quasi-static three-point bending tests, with results showing significantly improved mechanical stiffness and strength over traditional pouch cells. The rivets minimize interlayer shear movement of the electrode stack, thus allowing it to maintain electrochemical functionalities while carrying mechanical bending. While minimal load application can cause permanent deformation of pouch cells, MESCs maintain their structural integrity and energy-storage capabilities under realistic repeated loading. The results obtained demonstrate the mechanical robustness of MESCs, which allow them to be fabricated as energy-storing structures for electric vehicles and other applications.
The authors introduce advanced technology for controlled wireless light delivery in optogenetics applications with real-time user programming capacity. The utility of the platform is highlighted by induction of neural synchrony to modify social behavior in mice.
This paper studies the prototype development for the self-propelled capsule system which is driven by autogenous vibrations and impacts under external resistance forces. This project aims for proof-of-concept of its locomotion in pipeline environment in order to mitigate the technical complexities and difficulties brought by current pressure-driven pipeline inspection technologies. Non-smooth multibody dynamics is applied to describe the motion of the capsule system, and two non-smooth nonlinearities, friction and impact, are considered in modelling. The prototype of the self-propelled capsule system driven by a push-type solenoid with a periodically excited rod has been designed to verify the modelling approach. The prototype contains a microcontroller, a power supply, and a wireless control module, which has been tested in a clear uPVC pipe via remote control. Various control parameters, e.g. impact stiffness, frequency and amplitude of excitation, are studied experimentally, and finally, the fastest progression of the system is obtained.
A lithium-ion battery was developed using off-the-shelf pouch cells and launched with a small scientific satellite “REIMEI.” The cells were potted with polyurethane or epoxy resin to protect the battery from vacuum in space. Preliminary experimental test results of pouch cells potted in a soft aluminum cap suggested that the cells tended to swell in vacuum, although they had been reinforced with the resins. Bread board models (BBMs), in which pouch cells were potted with resins in a hard aluminum case, were fabricated for cycle life performance tests in the laboratory. The test results indicated that the performance of epoxy-potted BBM was superior to that of the polyurethane-potted BBM. The measured cell resistance implied that the electrolyte solution leaked through the polyurethane resin, resulting in premature deterioration. The epoxy resin was used for the flight battery. The end-of-discharge-voltage (EoDV) trend of the flight battery on orbit was compared with the laboratory test results corrected based on a post-launch cycle test using a fresh cell. The corrected EoDV trend in the laboratory was in good agreement with the on-orbit trend for the early cycle period, indicating that the on-orbit battery was not inadvertently affected by conditions in space.
Lithium insertion mechanism in some antimony-based compounds: SnSb, CoSb3, CrSb2, TiSb2 has been studied by means of 121 Sb Mössbauer spectrometry which gives valuable information about the local electronic structure of the probed element (Sb). The structural and electronic modifications induced by insertion of lithium have been characterized. For these Sb-based materials the lithium insertion mechanisms involve Li3Sb formation and composite multi-phase separations with one component displaced from the pristine compound.
Competitive costs, instant recharge, and high energy density make fuel cells ideal for supplanting batteries in portable electronic devices. In this study, we derive a semi-analytical model to elucidate the transport of ions, heat and mass in air-breathing fuel cells. The model includes an empirical correlation for membrane conductivity that improves accuracy when modelling membrane dry-out. A detailed comparison with experimental data demonstrates that the model accurately predicts fuel cell performance through detailed accounting of catalyst layer specifications, including variable width, and electrochemical parameters. A comprehensive parametric study resolves the trends associated with a variety of design specifications and operating conditions. Membrane dry-out is identified as the primary limitation on current density, and is shown to be strongly dependent on heat transfer. The study also identifies some unique effects of coupling between ambient air temperature and humidity on the performance of air-breathing fuel cells.
Spinel LiAl0.05Mn1.95O4 has been successfully synthesized by a new ultrasonic-assisted sol–gel (UASG) method. The structure and physicochemical properties of this as-prepared powder compared with the pristine LiMn2O4 and LiAl0.05Mn1.95O4 synthesized by the traditional sol–gel method were investigated by differential thermal analysis (DTA) and thermogravimetery (TG), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry (CV), and galvanostatic charge–discharge testing in detail. The results show that all samples have high phase purity, and ultrasonic process plays an important role in controlling morphology; LiAl0.05Mn1.95O4 has higher Mn oxidation state, and the absorption peak of Mn(III)O and Mn(IV)O bonds has blue shift because of the doped Al. CV confirms that the LiAl0.05Mn1.95O4 sample (UASG) has a good reversibility and its structure is very advantageous for the transportation of lithium ions. The charge–discharge tests indicate that LiAl0.05Mn1.95O4 (UASG) has nearly equal initial capacity with LiMn2O4 (sol–gel) at 1C discharge rate, but LiAl0.05Mn1.95O4 (UASG) has higher discharge potential than that of LiMn2O4 (sol–gel). In addition, LiAl0.05Mn1.95O4 (UASG) has higher discharge potential and capacity than that of LiAl0.05Mn1.95O4 (sol–gel) at 1C discharge rate, and LiAl0.05Mn1.95O4 (UASG) has high capacity retention at C/3 and 1C discharge rate among three samples after 50 cycles, which reveals that the sample obtained via UASG method, has the best electrochemical performance among three samples.
This paper introduces an electrical battery model. Based on a Thévenin circuit with two RC parallel branches, it includes an ampère-hour counting method to estimate the state of charge (SOC) and a novel model for the hysteresis. The presented model can consider variations in its parameters under changes in all of its internal and external variables, although only SOC and hysteresis are considered. Hysteresis consideration does not only allow distinguishing the parameters during charging and discharging, but also during transients between them. The model was designed to be capable of being implemented in online and offline systems. Finally the proposed model was validated for a single Ni–Cd cell, characterized by current interruption method, in an offline system. The validation was also extended to a stack of 210 cells of the same technology.
Renewable energy-based off-grid or decentralised electricity supply has traditionally considered a single technology-based limited level of supply to meet the basic needs, without considering reliable energy provision to rural consumers. The purpose of this paper is to propose the best hybrid technology combination for electricity generation from a mix of renewable energy resources to satisfy the electrical needs in a reliable manner of an off-grid remote village, Palari in the state of Chhattisgarh, India. Four renewable resources, namely, small-scale hydropower, solar photovoltaic systems, wind turbines and bio-diesel generators are considered. The paper estimates the residential, institutional, commercial, agricultural and small-scale industrial demand in the pre-HOMER analysis. Using HOMER, the paper identifies the optimal off-grid option and compares this with conventional grid extension. The solution obtained shows that a hybrid combination of renewable energy generators at an off-grid location can be a cost-effective alternative to grid extension and it is sustainable, techno-economically viable and environmentally sound. The paper also presents a post-HOMER analysis and discusses issues that are likely to affect/influence the realisation of the optimal solution.
A soluble polyimide (PI) is attempted to be a binder for transition metal oxide cathode in lithium ion batteries. It is synthesized from 2,2-Bis[4-(4-aminophenoxy)phenyl]propane, 4,4′-Oxydianiline and 4,4′-Oxydiphthalic anhydride, and characterized by FT-IR and 1H NMR techniques. To be a binder, the synthesized PI is applied to fabricate the electrodes, showing binding property and electrochemical performance as good as poly(vinylidene fluoride) (PVDF) that is conventional binder widely used in lithium ion batteries. The 2 Ah pouch full cells with PI and PVDF binders are assembled to compare their performances. As a result, the batteries with PI binder display 91.4% capacity retention after 500 cycles, which is almost the same as the cells withPVDF binder. The overcharge safetytests are carried by 2 Ah pouch full cells, indicating that PI cells can pass the test, no fire and no explosion, but the PVDF cells fail the test, catching fire. The result shows that the PI binder can enhance the safety of Li-ion batteries. This study paves a new way to improve the safety performance of lithium ion batteries.
Mechanical properties and lithiation-induced stress are crucial to the performance and durability of lithium-ion batteries. Here, we report the evolution of elastic modulus and stress in a silicon/polyvinylidene fluoride (PVDF) composite electrode coated on a copper foil, along with a model for analyzing the large change in the radius of curvature of the composite electrode/copper foil cantilever. The radius of curvature of the cantilever is captured by a video camera during lithiation/delithiation. The elastic modulus of the composite electrode decreases from about 0.64 GPa to 0.18 GPa during lithiation. It decreases further to about 0.10 GPa after delithiation, which is caused by the fracture of the electrode. The magnitude of the compressive stress increases lineally during lithiation and decreases suddenly to reach a steady state value during delithiation.
Rechargeable batteries based upon sodium (Na+) cations are at the core of many new battery chemistries beyond Li-ion batteries. Rather than using carbon or alloy-based anodes, the direct utilization of solid sodium metal as an anode would be highly advantageous, but its use has been highly problematic due to its high reactivity. In this work, it is demonstrated that, by tailoring the electrolyte formulation, solid Na metal can be electrochemically plated/stripped at ambient temperature with high efficiency (>99%) on both copper and inexpensive aluminum current collectors thereby enabling a shift in focus to new battery chemical couples based upon Na metal operating at ambient temperature. These highly concentrated electrolytes have enabled excellent cycling stability of Na metal batteries using Na metal anode and Na3V2(PO4)3 cathode at high rates with very high efficiency.
The safety of lithium-ion batteries under mechanical abuse conditions is an essential feature where these cells are used in mobile applications such as electric vehicles. In recent publications, punch testing has been used as a benchmark to study the mechanical abuse tolerance of the cells. What has not been studied in depth is how various test conditions such as the loading rate or the location of indentation affect the response of the cell. This paper quantifies the effects of four important test variables on the results of mechanical indentation tests. The first factor studied was to what degree tests on dry dummy cells without electrolyte can predict the response of a production cell. Then the effects of loading location, center versus on the edge, was evaluated. The speed of the test, at quasi-static rates, was the third variable. The last test characteristic studied was the repeatability of punch loading experiments. After completing the test program, a finite element model was developed to simulate the response of all studied cases. The model showed good predictability of load-displacement response and the onset of short circuit under all loading scenarios studied in this research.
Galvanodynamic synthesis is introduced as a new flexible electrochemical method for the preparation of electroactive materials, as utilized for electropolymerization of aniline in the present seminal work. It is indeed a missing method in the four possible electrochemical methods namely potentiodynamic, potentiostatic, galvanostatic, and finally galvanodynamic. This explicit comparative study shows the flexibility of this method in controlling the physical and electrochemical properties of the polyaniline film. Electrochemical polymerization was performed by scanning the current in a given range. Different approaches for this purpose were also introduced as the synthesis can be performed under different conditions through linear scanning, cyclic scanning, and repetitive cyclic scanning. Effects of various controllable parameters, such as scan rate, the current range, and the scan direction were also examined. In comparison with other electrochemical methods, galvanodynamic synthesis has higher flexibility to alter controllable parameters in favor of a specific application. For instance, synthesis of polyaniline to display characteristic redox peaks suitable for battery performance or strong capacitive behavior ideal for supercapacitors.
Lithium–oxygen batteries promise high energy but suffer from poor cycle life owing to the generation of highly reactive singlet oxygen 1O2, which rapidly deactivates the electrode and the electrolyte. Here we demonstrate an effective strategy to suppress 1O2 using redox mediators. Using operando spectroscopy techniques, we show that 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), as a model redox mediator, drastically reduces 1O2 formation, increases the yield of ground state 3O2, and reduces the by-product generation. The 1O2 suppression effect is attributed to an increased intersystem crossing rate induced by redox mediators, with which the relaxation of a singlet-state intermediate to a triplet-state one is accelerated. We further show that this 1O2 suppression effect applies universally across six common redox mediators with up to three orders of magnitude higher 1O2 suppression efficiency compared to 1,4-diazabicyclo[2.2.2]octane (DABCO), the most efficient quencher used in Li–O2 batteries to date. From the comparison of the investigated mediators we discuss the plausible governing principle dictating redox mediators’ effectiveness in suppressing 1O2. Our study achieves effective 1O2 suppression and provides guidelines for designing redox mediators for efficient and reversible lithium–oxygen batteries.
Reliable state estimate depends largely on an accurate battery model. However, the parameters of battery model are time varying with operating condition variation and battery aging. The existing co-estimation methods address the model uncertainty by integrating the online model identification with state estimate and have shown improved accuracy. However, the cross interference may arise from the integrated framework to compromise numerical stability and accuracy. Thus this paper proposes the decoupling of model identification and state estimate to eliminate the possibility of cross interference. The model parameters are online adapted with the recursive least squares (RLS) method, based on which a novel joint estimator based on extended Kalman Filter (EKF) is formulated to estimate the state of charge (SOC) and capacity concurrently. The proposed joint estimator effectively compresses the filter order which leads to substantial improvement in the computational efficiency and numerical stability. Lab scale experiment on vanadium redox flow battery shows that the proposed method is highly authentic with good robustness to varying operating conditions and battery aging. The proposed method is further compared with some existing methods and shown to be superior in terms of accuracy, convergence speed, and computational cost.
Publisher Summary This chapter provides various processes for producing polymer thin films, but whatever the deposition process (extrusion coating, wet or dry methods), the properties of the resulting film will depend strongly on the chemical nature of the polymer used. However, the numerous interactions between the process and material parameters significantly influence the final properties. Also it is very important to control the process parameters for maximum optimization of the target properties. With control of these processes becoming more and more developed, films with an increasingly fine structure can be obtained (e.g. nanometric scale for PECVD). This in turn produces properties with very high performance. The resulting thin films are used by traditional industries such as packaging and steel, but because there is enormous progress in the area of structure and properties, new emerging markets are focusing on the latest generation of polymer films.
We assessed residual cognitive deficits in young people with idiopathic and cryptogenic epilepsy. In the setting of an ongoing prospective study, we invited participants initially diagnosed and enrolled in the cohort 8–9 years earlier to undergo standardized neuropsychological assessment. Sibling controls were invited when available. We analyzed 143 pairs in which cases had idiopathic or cryptogenic epilepsy and both case and control had normal intelligence. Compared with that for siblings, the Full Scale IQ for cases was 3.3 points lower (P =0.01) mainly due to slower processing speed, which was 5.6 points lower (P =0.0004). Word reading (P =0.04) and spelling (P =0.01), but not other scores, were also lower in cases. Remission status and drug use did not influence findings. In young people of normal intelligence with idiopathic or cryptogenic childhood-onset epilepsy, substantial residual effects of epilepsy appear to be confined largely to slower processing speed.
A spherical lithium-rich layered cathode material with an average composition of Li1.13[Mn0.534Ni0.233Co0.233]0.87O2 was successfully synthesized via co-precipitation route. In this material, each particle was consisted of an inner core and a stable concentration-gradient outer layer in which manganese content was gradually increased. The concentration-gradient material showed a typical rhombohedral LiNiO2-like layered structure with the existence of the monoclinic Li2MnO3-type integrated component. It can be found from the cross-sectional SEM images that the concentration-gradient particle was quite homogeneous without any apparent gap between the inner core and the concentration-gradient outer layer. Furthermore, according to the EDXS analysis, the concentrations of Mn, Ni, and Co kept almost constant throughout the core, and the concentration of Mn increased gradually within the outer layer of the particle. The lithium-rich layered material can deliver a very high capacity of 220 mAh g−1, and the excellent cycle life and improved thermal stability were achieved by the concentration-gradient outer layer. The results here indicate that the lithium-rich layered material with a manganese-rich concentration-gradient outer layer will be a promising cathode material for advanced lithium ion batteries with high capacity, long cycle life, and improved safety.