Cathode Electrode Research Articles

Design and Optimization of Microbial Fuel Cells and Evaluation of a New Air-Breathing Cathode Based on Carbon Felt Modified with a Hydrogel—Ion Jelly®

The increased demand for alternative sustainable energy sources has boosted research in the field of fuel cells (FC). Among these, microbial fuel cells (MFC), based on microbial anodes and different types of cathodes, have been the subject of renewed interest due to their ability to simultaneously perform wastewater treatment and bioelectricity generation. Several different MFCs have been proposed in this work using different conditions and configurations, namely cathode materials, membranes, external resistances, and microbial composition, among other factors. This work reports the design and optimization of MFC performance and evaluates a hydrogel (Ion Jelly®) modified air-breathing cathode, with and without an immobilized laccase enzyme. This MFC configuration was also compared with other MFC configuration performances, namely abiotic and biocathodes, concerning wastewater treatment and electricity generation. Similar efficiencies in COD reduction, voltage (375 mV), PD (48 mW/m2), CD (130 mA/m2), and OCP (534 mV) were obtained. The results point out the important role of Ion Jelly® in improving the MFC air-breathing cathode performance as it has the advantage that its electroconductivity properties can be designed before modifying the cathode electrodes. The biofilm on MFC anodic electrodes presented a lower microbial diversity than the wastewater treatment effluent used as inocula, and inclusively Geobacteracea was also identified due to the high microbial selective niches constituted by MFC systems.

Optimisation and characterisation of graphene-based microporous layers for polymer electrolyte membrane fuel cells

The viability of graphene-based microporous layers (MPLs) for polymer electrolyte membrane fuel cells is critically assessed through detailed characterisation of the morphology, microstructure, transport properties and electrochemical characterisation. Microporous layer composition was optimised by the fabrication of several hybrid MPLs produced from various ratios of graphene to Vulcan carbon black. Single cell tests were performed at various relative humidities between 25% and 100% at 80 °C, in order to provide a detailed understanding of the effect of the graphene-based MPL composition on the fuel cell performance. The inclusion of graphene in the MPL alters the pores size distribution of the layer and results in presence of higher amount of mesopores. Polarisation curves indicate that a small addition of graphene (i.e. 30 wt %) in the microporous layer improves the fuel cell performance under low humidity conditions (e.g. 25% relative humidity). On the other hand, under high humidity conditions (≥50% relative humidity), adding higher amounts of graphene (≥50 wt %) improves the fuel cell performance as it creates a good amount of mesopores required to drive excess water away from the cathode electrode, particularly when operating with high current densities.

Surface plasmon resonance effects of silver nanoparticles in graphene-based dye-sensitized solar cells

Localized surface plasmon resonance (LSPR) has been applied in photovoltaic devices to improve their photoelectric conversion efficiency. In this study, the mechanism of LSPR in dye-sensitized solar cells (DSSCs) was determined. Specifically, silver nanoparticles were formed by evaporating silver in electro-beam equipment and then annealing it in a tube furnace. The sizes of the nanoparticles varied with the changes in their thicknesses during evaporation and annealing. A DSSC-based graphene was designed to consist of different sizes of metal nanoparticles assembled on a cathode electrode. The photon electric performance of the DSSCs, which depended on Ag nanoparticles, was analyzed in detail, with a particular focus on nanoparticle size. Compared with the DSSC without Ag nanoparticles, the DSSC with LSPR exhibited excellent electric current density and incident photon-to-current efficiency (IPCE) performance due to the LSPR effect. The DSSC assembled with 10 nm-thick Ag film and annealed to form nanoparticles exhibited a high IPCE of 70.03%. The IPCE value of this DSSC was 45.15% higher than that of the pure graphene-based DSSC (31.62%). However, Ag nanoparticles increased to a certain degree and became aggregated and concatenated, thereby decreasing the LSPR effect on DSSCs. Therefore, LSPR plays an important role in the photon-electrical performance of DSSCs.

Coupling Single-Ni-Atom with Ni–Co Alloy Nanoparticle for Synergistically Enhanced Oxygen Reduction Reaction

Developing nonprecious metal-based oxygen reduction reaction (ORR) electrocatalysts with superior activity and durability is crucial for commercializing proton-exchange membrane (PEM) fuel cells. Herein, we report a metal-organic framework (MOF)-derived unique N-doped hollow carbon structure (NiCo/hNC), comprising of atomically dispersed single-Ni-atom (NiN4) and small NiCo alloy nanoparticles (NPs), for highly efficient and durable ORR catalysis in both alkaline and acidic electrolytes. Density functional theory (DFT) calculations reveal the strong coupling between NiN4 and NiCo NPs, favoring the direct 4e- transfer ORR process by lengthening the adsorbed O-O bond. Moreover, NiCo/hNC as a cathode electrode in PEM fuel cells delivered a stable performance. Our findings not only furnish the fundamental understanding of the structure-activity relationship but also shed light on designing advanced ORR catalysts.

Improving the Electrochemical Performance of Core–Shell LiNi0.8Co0.1Mn0.1O2 Cathode Materials Using Environmentally Friendly Phase Structure Control Process

The phase structure of the precursor is crucial for the microstructure evolution and stability of Ni-rich cathode materials. Using sodium lactate as a green complexing agent, cathode electrode materials with different phase structures and unique core–shell structures were prepared by the co-precipitation method in this study. The influence of the phase structure of the nickel-rich precursor on the cathode electrode materials was studied in depth. It was found that α-NCM811 had large interlayer spacing, which was beneficial for the diffusion of lithium ions. In contrast, β-NCM811 had smaller interlayer spacing, a good layered structure, and lower ion mixing, resulting in better cycling performance. The core–shell-αβ-NCM811 with α-NCM811 as the core and β-NCM811 as the shell was prepared by combining the advantages of the two different phases. The core–shell-αβ-NCM811 showed the highest discharge capacity of 158.7 mAh/g at 5 C and delivered excellent rate performance. In addition, the β-NCM811 shell structure with smaller layer spacing could prevent corrosion of the α-NCM811 core by the electrolyte. Thus, the capacity retention rate of the core–shell-αβ-NCM811 was still as high as 86.16% after 100 cycles.

Bilateral transcranial direct-current stimulation promotes migration of subventricular zone-derived neuroblasts toward ischemic brain.

Ischemic insult stimulates proliferation of neural stem cells (NSCs) in the subventricular zone (SVZ) after stroke. However, only a fraction of NSC-derived neuroblasts from SVZ migrate toward poststroke brain region. We have previously reported that direct-current stimulation guides NSC migration toward the cathode in vitro. Accordingly, we set up a new method of transcranial direct-current stimulation (tDCS), in which the cathodal electrode is placed on the ischemic hemisphere and anodal electrode on the contralateral hemisphere of rats subjected to ischemia-reperfusion injury. We show that the application of this bilateral tDCS (BtDCS) promotes the migration of NSC-derived neuroblasts from SVZ toward the cathode direction into poststroke striatum. Reversing the position of the electrodes blocks the effect of BtDCS on the migration of neuroblasts from SVZ. BtDCS protects against neuronal death and improves the functional recovery of stroke animals. Thus, the migration of NSC-derived neuroblasts from SVZ toward poststroke brain region contributes to the effect of BtDCS against ischemia-induced neuronal death, supporting a potential development of noninvasive BtDCS as an endogenous neurogenesis-based stroke therapy.

Perovskite rare earth porous hollow microspheres of SmFeO3/MWCNT battery type asymmetric hybrid supercapacitors

The rapid advancements made by science and technology in the present world are astonishing and have a way of stimulating our imagination. Modern research centres on search for unique cathode electrodes to improve energy density in hybrid supercapacitors (HSCs). A battery-type perovskite rare earth-based SmFeO3/MWCNT electrode is being investigated as cathode electrode for future-generation energy storage devices. Herein, perovskite rare earth-based metal oxides and its carbon composites (SmFeO3, SmFeO3/GC,SmFeO3/MWCNT) are flourishingly synthesized via one-step solvothermal technique as cathode materials for hybrid supercapacitors. The asymmetric solid-state supercapacitor SmFeO3/MWCNT//CNT device is constructed with an excellent 216.68 F/g specific capacitance, 67.71 Wh/kg energy and 749.97 W/kg power density at 1 A/g current density. An improved cycling performance of 79.83% capacity retention and 99.84% coulombic efficiency after 20000 long-cycles is reported. This work revealed that SmFeO3/MWCNT//CNT AHSSCs offer boundless ability as good electrode for practical energy storage applications.

Degradation of emerging pollutants on bifunctional ZnFeV LDH@graphite felt cathode through prominent catalytic activity in heterogeneous electrocatalytic processes

The heterogeneous Electro-Fenton (EF) process is a promising wastewater treatment technology that can generate onsite H2O2, and operate in a wide pH range without generating a metal sludge. However, the heterogeneous EF process needs bifunctional cathode electrodes that can have high activity in 2e− oxygen reduction reaction and H2O2 decomposition. Herein, ZnFeV layered double hydroxide (LDH), as a heterogeneous catalyst, was coated on the graphite felt (ZnFeV LDH@GF) cathode using the electrophoretic deposition method. ZnFeV LDH@GF cathode was able to generate 59.8 ± 5.9 mg L−1 H2O2 in 90 min under a constant supply of O2. EF process with ZnFeV LDH@GF cathode exhibited 89.8 ± 6.8% removal efficiency for pharmaceutical (ciprofloxacin) at neutral pH. Remarkably, the apparent reaction rate constant (kapp) of the ZnFeV LDH@GF-EF was 2.14 times that of the EF process with pristine GF. ZnFeV LDH coating increased the hydroxyl radical (•OH) production of the EF process from 1.74 mM to 3.65 mM. The pathway of •OH production is thought to be a single electron transfer from redox couples of Fe2+/Fe3+ and V4+/V5+ to H2O2. After 10 reuse cycles, the ZnFeV LDH@GF cathode retained 90.2% of its efficiency. Eight intermediate compounds were identified by GC-MS including cyclic compounds and aliphatic compounds.

Combination of H2O2-producing microbial desalination cells and UV/H2O2 advanced oxidation process: Water salinity reduction and microbial inactivation

Microbial desalination cells (MDCs) are bioelectrochemical devices that can recover usable energy and chemicals from organic wastes and concurrently desalinate saltwater. MDCs can also produce the green oxidant, H2O2, through a two-electron oxygen reduction reaction occurring on the cathode electrode. If MDCs producing H2O2 are used in the pretreatment of brackish water or seawater for reverse osmosis (RO) processes, the salinity of feed water can be reduced in MDCs and the MDC-produced H2O2 can be utilized onsite to oxidize organic contaminants or disinfect microorganisms in the feed water. This strategy of using MDC pretreatment may substantially alleviate the energy requirements and biofouling tendency of downstream RO units. Herein, we assessed the applicability of a combination of H2O2-producing MDCs and ultraviolet (UV) or UV254nn -based advanced oxidation process (AOP) (i.e., UV/H2O2) as pretreatment for RO processes. We first examined the effect of catholyte conditions, which is one of the most crucial factors directly affecting the H2O2 composition and decomposition, on the performance of MDCs. Then, we evaluated the microorganism disinfection efficiencies of advanced photo-oxidation processes using H2O2 obtained from MDCs. The MDC investigated herein achieved 93.1% desalination efficiency and > 5.0 mM H2O2 concentration. In addition, UV-based AOP with the produced H2O2 demonstrated up to 15-fold higher inactivation kinetics than that by UV254 nm disinfection alone.

Hybrid Zinc Coatings with Chitosan/Alginate Encapsulated CuO-Nanoparticles for Anticorrosion and Antifouling Protection of Mild Steel

The construction of anticorrosion coatings containing antifouling agents is an effective way to ensure the long-term durability of marine steel infrastructures. In this work, an innovative hybrid coating was prepared by introducing biocide CuO nanoparticles in ordinary zinc coating to improve its protective ability for steel in aggressive salt water environments. The CuO nanoparticles were embedded inside the matrix of chitosan/alginate complexes to prevent spontaneous copper leaching during corrosive attacks. Two procedures were applied for the electrodeposition of hybrid/composite zinc-based coatings on low-carbon steel substrates (DC current): first—the co-electrodeposition of encapsulated CuO nanoparticles with zinc on a cathode (steel) electrode from a sulfate electrolyte with a relatively low pH value of about 4.5–5.0 and second—the encapsulated CuO nanoparticles were electrodeposited from aqueous solution as an intermediate layer between two zinc deposits. The particles size and stability of suspensions were evaluated using dynamic light scattering. Both hybrid coatings were compared in terms of surface morphology and hydrophilicity (SEM and AFM analysis, contact angle measurement) and corrosion resistance (potentiodynamic polarization curves, polarization resistance). The protective characteristics of the coatings were compared in a 3.5% NaCl solution and artificial sea water. The hybrid coating showed 2–4 times higher polarization resistance than the bare zinc coating during a 30 day immersion in artificial sea water, indicating that this coating has the necessary characteristics to be used in a marine environment.

Quadra layer core−shell−core−shell structured Co9S8@MnS-NC nanorod composites for enhanced sodium-ion batteries

The dramatic volume expansion of transition metal sulfides has inhibited their widely usage despite of high theoretical capacity. In this work, the Co9S8@MnS-NC composite with novel sandwich-like structure is fabricated by a multi-step reaction. The micro/nano-sized Co9S8@MnS-NC is characteristic with stable hierarchical structure, the inner Co9S8 particles are protected by carbon rod, which is also covered by MnS shell and an external conductive carbon shell. The unique double core-shell structure promotes double protective effect, making it better to adapt to the volume expansion and maintain the structural integrity of the active Co9S8 core. The synergistic effect induced by bimetallic sulfides and N-doped carbon helps to enhance conductivity, cyclic stability and transport efficiency of charge carrier. As a result, the corncob-like Co9S8@MnS-NC delivers a high reversible capacity (444.7 mAh·g−1 at 100 mA·g−1) and a well-designed cyclic stability of 96% after 2000 cycles at 3000 mA g−1. Notably, the matching cathode electrode Na3V2(PO4)3 is assembled with Co9S8@MnS-NC to achieve the full cell with a high-performance reverse capacity (248.7mAh·g−1). The huge improvement of electrochemical activity and structural stability could be attributed to the MnS nanoparticles anchored on Co9S8 and the protective effect of the double carbon layer. This study suggests an effective approach to improve the electrochemical performance of bimetallic sulfide.

The pinhole effect on proton exchange membrane fuel cell (PEMFC) current density distribution and temperature distribution

The proton exchange membrane (PEM) is a critical portion of a proton exchange membrane fuel cell (PEMFC). However, it is strongly influenced by pinhole defects owing to degradation during its operation or manufacture. Such defects may accelerate chemical polymer decomposition, eventually causing fuel cell failure and other safety issues. Thus, it is necessary to detect and characterize pinhole degradation while determining the effect of pinhole on electrochemical behavior and fuel cell performance. Herein, pinholes of different sizes (10 and 100 µm) were fabricated on a 50-cm2 catalyst-coated membrane (CCM) and characterized using commercial current scan shunt (CSS) S++ Simulation Services (Hephas Energy) to investigate the effects of pinhole size on current density and temperature distributions of the PEMFC. Our analyses show that hydrogen crossover from the anode to the cathode through a pinhole can cause hydrogen diffusion and a hydrogen oxidation reaction (HOR) on the cathode electrode surface under certain conditions. Consequently, local reverse currents and hot spots are detected around the pinhole position under open-circuit voltage (OCV) and the corresponding current and temperature distribution trends are uniform. Conversely, the reverse current immediately disappeared from the current distribution map because water exists under operation conditions, resulting in membrane swelling and pinhole sealing. Thus, hydrogen crossover decreased and local reverse currents reappeared as a result of anode overpressure during fuel cell operation. The local reverse current becomes weaker when using the same-sized pinhole under the same anode overpressure because the overall current density increases. Furthermore, owing to the presence of water, the capillary force for the 100-µm pinhole was higher than that for the 10-µm pinhole, indicating that more anode overpressure is required to generate a local reverse current. Thus, the position and size of the pinhole can be effectively detected using in situ characterization.

Roll-to-roll solvent-free manufactured electrodes for fast-charging batteries

Roll-to-roll solvent-free manufactured electrodes for fast-charging batteries

Investigation of the Effective Voltage and Performance of Thermocells

Thermocells, also called thermogalvanic cells, are a promising technology that can efficiently harvest low-grade waste heat with direct thermoelectric conversion. The cells operate under a temperature difference, with one electrode on the hot side and the other on the cold side. The recently developed electrodes, such as porous carbon materials and pin-structured electrodes, have led to a temperature gradient even inside one of the electrodes. However, it still remains an open question of what temperature difference determines the open-circuit voltage of thermocells. Here, we investigated the effective voltage of a thermocell with thick electrodes. The temperature difference that determines the voltage turned out to be the smallest temperature difference between anode and cathode electrodes, the average temperature difference, or in between, depending on the internal resistances of the cell. We also verified the validity of normalized power density estimated from the open-circuit voltage. In addition, a strategy was demonstrated to improve the power density of a thermocell that consists of thick electrodes. The results provided here would help devise high-performance thermocells with optimized electrode structures.

Digital Fabrication and Reliability Evaluation Method for G-Band TWT Electron Optical System

Terahertz traveling wave tubes (THz-TWTs) electron optical system (EOS) has strict fabrication accuracy requirements. The low reliability of traditional manual assembly always is the direct problem hindering the development of TWT to high frequency, high power, high efficiency, and high reliability. In this article, a digital fabrication and reliability evaluation method for THz-TWTs EOS was presented. First of all, through improving the gun shell structure and sealing molds, developing automatic and semi-automatic assembly methods, writing automatic geometric measure programs, measuring the thermal deformation of cathode and focusing electrode (FE) under working temperature, etc., the implementation of digital fabrication technology was completed, which promoted the fabrication accuracy (1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma \text{)}$</tex-math> </inline-formula> to 3–10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula> m and 0.05 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> –0.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> . Then, in order to find the tolerance limit to keep the electronic trajectory stable and the balance between design reliability and fabrication reliability, the CST particle solver single and multi-parameter sweep function was used to analyze the EOS of a 0.22 THz-TWT. Based on the digital fabrication technology process capability, 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma $</tex-math> </inline-formula> quality management theory, and equal proportion compress single parameter tolerance limit method, we defined four independent sensitive parameters, and calculated the reliability of THz-TWT EOS digital fabrication was not less than 72.47% by MINITAB software. This method can be used as a quantitative calculation of whether the TWT EOS design and fabrication are matched, and give appropriate tolerance and compensation range in the actual TWT fabrication process.

Investigation of Delay Jitter of Avalanche GaAs PCSS for Triggering High-Voltage Gas Switch

The delay jitter characteristics of gallium arsenide (GaAs) photoconductive semiconductor switches (PCSSs) triggered in avalanche mode were experimentally investigated under dc bias. In the dark-state measurement, the PCSS was tested under a 40-kV bias voltage to verify its withstanding voltage and reliability. In the ON-state measurement, the delay jitter time of PCSS at different triggering positions was measured. The experimental results showed that the shortest delay jitter time was obtained when the laser was applied to the middle position of the cathode electrode. To evaluate the long-time stability, the delay-jitter time was recorded after continuous shots. It shows an ascending trend in delay jitter time with the increase in operating shots. The degeneration of the delay jitter time of the PCSS was mainly attributed to the device damage, including electrode ablation and filament current ablation, which was verified by the analysis of scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). Furthermore, a bipolar high-voltage gas switch integrated with PCSSs was successfully triggered by a low-energy fiber laser.

S-Doped Graphene Oxide/N-Doped Graphene Oxide/PANI: A Triple Composite for High-Performance Supercapacitor Applications

In this study, nitrogen doped graphene oxide(N-GO) and sulfur doped graphene oxide(S-GO) were produced in one step, and two of these prepared materials were converted into composite form with polyaniline(PANI). For the first time in the literature, triple composite electrode materials with two heteroatom doped graphene oxides and PANI were prepared for supercapacitors. In this context, heteroatom doped graphene oxides and PANI were characterized using spectroscopic and microscopic methods. With the ternary composites formed, anode and cathode electrode materials for coin cell type supercapacitors in asymmetrical form were characterized by electrochemical methods. The capacitive behavior of the prepared supercapacitors was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) method. The change of capacitive behavior according to the number of cycles was determined by cyclic charge-discharge tests. With the electrode materials obtained with heteroatom doped graphene oxides/PANI composites, it reached the highest areal capacitance value of 79.7 mF.cm−2 at 10 mV.s−1 scan rate. The coin cell type asymmetric supercapacitors retained more than 100% of their initial specific capacitance at the end of the 1500 cycle.

Electrodeposition of bimetal Ni-Co oxide as a bifunctional electrocatalyst for rechargeable zinc air battery

Zinc air battery is a promising candidate green energy storage due to its high energy density and low-cost. However, most of the preparation of air cathode in the literature involves a lengthy and inefficient process of mixing catalyst powders with a polymeric binder. Herein, we synthesize bimetal Ni-Co oxide through a simple electrodeposition technique followed by annealing at a low temperature under atmospheric conditions. The addition of cobalt at various contents significantly alters surface morphology from tiny nanoparticles to a 2D nano-sheet structure. The performance of the as-prepared catalysts were firstly evaluated toward the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in alkaline solution. Our results show that the incorporating cobalt in the NiO host structure not only improve the OER but also the ORR activities. The required potential to drive OER at a current density of 10 mA/cm2 and the half-wave potential for ORR using the NC-2 catalyst are 1.567 and 0.855 V vs. RHE, respectively, resulting a delta potential of 0.712 V. Furthermore, we demonstrate the practical application of the NC-2 catalyst as the air cathode electrode for assembling a liquid zinc air battery device. The battery test reveals that NC-2 has an open circuit potential of 1.36 V and a specific capacity of 714 mAh/gZn with an excellent stability performance for about 80 h. Our findings suggest that bimetal Ni-Co oxide is a promising catalyst for enhancing the performance of zinc air batteries.

4 mA tDCS improves walking ability in PSP: A case study (P9-11.012)

<h3>Objective:</h3> The objective is to examine if tDCS can improve gait speed in people living with Progressive Supranuclear Palsy (PSP). <h3>Background:</h3> There is no current treatment for PSP. Neuromodulation with transcranial direct current stimulation (tDCS) works through modulating spontaneous activity of neural regions receiving electrical stimulation. The success of tDCS in individuals with motor-related diseases (Parkinson’s Disease and Stroke) indicates that it might be beneficial to individuals with PSP. Our lab (Chertkow-Roncero) has modeled electrical flow, finding that with two anode electrodes placed over the left and right deltoid muscles, and two cathode electrodes placed just ahead of the motor cortex on both sides (C3 &amp; C4), electrical stimulation occurs in midbrain and subthalamic regions. Using this PSP montage, a study from our lab has looked at the effects of tDCS on motor function in PSP, finding improvement persisting for a month. <h3>Design/Methods:</h3> An 84 year old lady with moderately severe PSP for 5 years and dependent on a walker, underwent two rounds of stimulation using the PSP montage, two months apart. Each round consisted of twelve tDCS sessions over three weeks. In the first week of both rounds, sham tDCS was given to establish a pre-stimulation baseline, while one of two real tDCS montages was given in weeks two and three of each round. tDCS was given at an intensity of 4 mA. Primary outcome measure was gait time which is the time required to walk four lengths of the gait mat(24 meters). <h3>Results:</h3> Significant improvement in gait time compared to baseline (26.84% improvement immediately after second round and 18.82% at 2 weeks post-stimulation) was noted after the second round. In both the rounds, she demonstrated improvement in cadence, stride length and stride velocity. <h3>Conclusions:</h3> These results suggest tDCS can provide a significant improvement in the walking ability of people living with PSP. <b>Disclosure:</b> Dr. Lahiri has nothing to disclose. Dr. Roncero has nothing to disclose. Miss Zhang has nothing to disclose. The institution of Dr. Chertkow has received research support from Hoffmann-La Roche Limited. The institution of Dr. Chertkow has received research support from Anavex Life Sciences. The institution of Dr. Chertkow has received research support from Alector Co.. The institution of Dr. Chertkow has received research support from Lilly.

Comprehensive investigation on the durability and safety performances of lithium-ion batteries under slight mechanical deformation

Mechanical abuse is a general abuse behavior in electric vehicles. To prevent the safety risk from mechanical deformation, it is necessary to understand its failure mechanism and its effects on battery performance. There is a knowledge gap in the influence of slight mechanical deformation on the durability and safety of lithium-ion batteries. This study comprehensively investigates the changes in electrochemical properties, morphology, and thermal stability in commercial ternary/graphite lithium-ion batteries by multiple techniques. Tested cells are indented from 4 mm to 6.8 mm and cycled for 620 cycles. The results of cycle aging exhibit that indentation can improve the cycle performance of tested cells, but the effect turns negative for the cells when the indentation depth exceeds 6.5 mm. The electrochemical impedance spectroscopy measurements exhibit that indentation retarded the increase of impedance of indented cells during the aging process. It could be due to the increase of compact density weakening the degradation in the anode electrode. But the degradation in the cathode electrode is aggravated by mechanical deformation. During the cycle aging of tested cells, the loss of lithium inventory dominates the degradation of indented cells in the first 500 cycles and then follows the loss of active material damage. The apparent morphology of electrodes in deformed and aged cells exhibits that active material particles are compacted in the dented area, and cracks are formed in the fold area. After cycle aging, the compressed area surrounding the dent is covered by a layer of reaction products of electrolyte with lithium at the anode electrode. The adiabatic tests show the thermal stability of indented cells reduces firstly and then increases with the increase of indentation depth, as well as the aged cells.