This study proposed a new information and commutation technology assisted blind telephone interview (ICT-ABTI) system to help visually impaired people to do telephone interview jobs as normal sighted people and create more diverse employment opportunities for them. The study also used an ABAB design to assess the system with seven visually impaired people. As the results, they can accomplish 3070 effective telephone interviews per month independently. The results also show that working performance of the visually impaired can be improved effectively with appropriate design of operation working flow and accessible software. The visually impaired become productive, lucrative, and self-sufficient by using ICT-ABTI system to do telephone interview jobs. The results were also shared through the APEC Digital Opportunity Center platform to help visually impaired in Philippines, Malaysia and China.
Bifunctional electrocatalysts to enable efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential for fabricating high performance metal-air batteries and fuel cells. Here, a defect rich nitrogen and sulfur co-doped graphene/iron carbide (NS-GR/Fe3C) nanocomposite as an electrocatalyst for ORR and OER is demonstrated. An ink of NS-GR/Fe3C is developed by homogeneously dispersing the catalyst in a Nafion containing solvent mixture using an ultrasonication bath (Model-DC150H; power - 150 W; frequency - 40 kHz). The ultrasonically prepared ink is used for preparing the electrode for electrochemical studies. In the case of ORR, the positive half-wave potential displayed by NS-GR/Fe3C is 0.859 V (vs. RHE) and for the OER, onset potential is 1.489 V (vs. RHE) with enhanced current density. The optimized NS-GR/Fe3C electrode exhibited excellent ORR/OER bifunctional activities, high methanol tolerance and excellent long-term cycling stability in an alkaline medium. The observed onset potential for NS-GR/Fe3C electrocatalyst is comparable with the commercial noble metal catalyst, thereby revealing one of the best low-cost alternative air-cathode catalysts for the energy conversion and storage application.
Nickel-rich (Ni > 90 %) cathodes are regarded as one of the most attractive because of their high energy density, despite their poor stability and cycle life. To improve their performance, in this study we synthesized a double concentration-gradient layered Li[Ni0.90Co0.04Mn0.03Al0.03]O2 oxide (CG-NCMA) using a continuous co-precipitation Taylor-Couette cylindrical reactor (TCCR) with a Ni-rich-core, an Mn-rich surface, and Al on top. The concentration-gradient morphology was confirmed through cross-sectional EDX line scanning. The as-synthesized sample exhibited excellent electrochemical performance at high rates (5C/10C), as well as cyclability (91.5 % after 100 cycles and 70.3 % after 500 cycles at 1C), superior to that (83.4 % and 47.6 %) of its non-concentration-gradient counterpart (UC-NCMA). The Mn-rich surface and presence of Al helped the material stay structurally robust, even after 500 cycles, while also suppressing side reactions between the electrode and electrolyte, resulting in better overall electrochemical performance. These enhancements in performance were studied using TEM, SEM, in-situ-XRD, XPS, CV, EIS and post-mortem analyses. This synthetic method enables the highly scalable production of CG-NCMA samples with two concentration-gradient structures for practical applications in Li-ion batteries.
The longlegged ant Anoplolepis gracilipes (Smith) is a highly invasive tramp ant species known for its deleterious effects on native ecosystems. While tramp ants are associated with human activity, information on how different intensities of human activity affect their distribution is limited. This study investigated how anthropogenic activities affected the distribution of A. gracilipes in Penang, a tropical island in northern peninsular Malaysia. Three study sites (Youth Park, Sungai Ara, and Bukit Jambul/Relau) were selected, containing four sub-locations corresponding to different levels of human activity (low, moderate, high, and very high), determined by the average number of passersby observed over 30 min. Baited index cards were placed at each sub-location to evaluate ant abundance and distribution. The results demonstrated that A. gracilipes worker abundance was highest in areas of moderate human activity, as opposed to areas with low and higher human activity. The low abundance of A. gracilipes in comparatively undisturbed localities may be attributed to unsuitable microclimate, lack of propagule pressure, and diminished honeydew availability. In contrast, its exclusion from more urbanized localities could be explained by high interspecific competition with other tramp species and the absence of preferred nesting sites.
The growing use of EVs and society's energy needs require safe, affordable, durable, and eco-friendly high-energy lithium-ion batteries (LIBs). To this end, we synthesized and investigated the removal of Co from Al-doped Ni-rich cathode materials, specifically LiNi0.9Co0.1Al0.0O2 (NCA-0), LiNi0.9Mn0.1Al0.0O2 (NMA-0), LiNi0.9Mn0.07Al0.03O2 (NMA-3), intending to enhance LIB performance and reduce the reliance on cobalt, a costly and scarce resource. Our study primarily focuses on how the removal of Co affects the material characteristics of Ni-rich cathode material and further introduces aluminum into the cathode composition to study its impacts on electrochemical properties and overall performance. Among the synthesized samples, we discovered that the NMA-3 sample, modified with 3 mol% of Al, exhibited superior battery performance, demonstrating the effectiveness of aluminum in promoting cathode stability. Furthermore, the Al-modified cathode showed promising cycle life under normal and high-temperature conditions. Our NMA-3 demonstrated remarkable capacity retention of ∼ 88 % at 25 °C and ∼ 81 % at 45 °C after 200 cycles at 1C, within a voltage range of 2.8-4.3 V, closely matching the performances of conventional NCM and NCA cathodes. Without cobalt, the cathodes exhibited increased cation disorder leading to inferior rate capabilities at high C-rates. In-situ transmission XRD analysis revealed that the introduction of Al has reduced the phase change and provided much-needed stability to the overall structure of the Co-free NMA-3. Altogether, the findings suggest that our aluminum-modified NMA-3 sample offers a promising approach to developing Co-free, Ni-rich cathodes, effectively paving the way toward sustainable, high-energy-density LIBs.
Rechargeable lithium-oxygen (Li-O2) batteries are being considered as the next-generation energy storage systems due to their higher theoretical energy density. However, the practical application of Li-O2 batteries is hindered by slow kinetics and the formation of side products during the oxygen reduction and evolution reactions on the cathode. These reactions lead to high overpotentials during charging and discharging. To address these challenges, we propose a simple ultrasonic method for synthesizing cobalt nanoclusters embedded in nitrogen-doped graphene nanosheets (GrZnCo) derived from metal-organic frameworks (MOFs). The resulting material, due to the retention of metallic cobalt structure, exhibits better electronic conductivity. Additionally, the GrZnCo catalyst shows vigorous catalytic activity, which can improve reaction kinetics and suppress side reactions, thus lowering the charging overpotential. We have investigated the impact of different catalyst compositions (GrZnCox; x = 1, 3, 5) by varying the amounts of cobalt and zinc. The optimum catalyst, GrZnCo3, contains high cobalt-N active components, graphitic-N, pyridinic-N, pyrrolic-N, and abundant defect structures, which enhance the electrochemical performance. The defect-rich GrZnCo3 catalyst enables Li-O2 batteries to achieve a high discharge capacity of 13500 mAh·g-1 at 50 mA·g-1 and a remarkable long-term cycling performance of over 400 cycles at 100 mA·g-1 with a limited capacity of 500 mAh·g-1. This work demonstrates an effective approach to fabricate cost-effective electrocatalysts for various energy storage systems.
Although solid-state Li-metal batteries (LMBs) featuring polymer-based solid electrolytes might one day replace conventional Li-ion batteries, the poor Li-ion conductivity of solid polymer electrolytes at low temperatures has hindered their practical applications. Herein, we describe the first example of using a co-precipitation method in a Taylor flow reactor to produce the metal hydroxides of both the Ga/F dual-doped Li7La3Zr2O12 (Ga/F-LLZO) ceramic electrolyte precursors and the Li2MoO4-modified Ni0.8Co0.1Mn0.1O2 (LMO@T-LNCM 811) cathode materials for LMBs. The Li/Nafion (LiNf)-coated Ga/F-LLZO (LiNf@Ga/F-LLZO) ceramic filler was finely dispersed in the poly(vinylidene fluoride)/polyacrylonitrile/lithium bis(trifluoromethanesulfonimide)/succinonitrile matrix to give a trilayer composite polymer electrolyte (denoted "Tri-CPE") through a simple solution-casting. The bulk ionic conductivity of the Tri-CPE at room temperature was approximately 4.50 × 10-4 S cm-1 and exhibited a high Li+ ion transference number (0.84). It also exhibits a broader electrochemical window of 1-5.04 V versus Li/Li+. A full cell based on a CR2032 coin cell containing the LMO@T-LNCM811-based composite cathode, when cycled under 1 C/1 C at room temperature for 300 cycles, achieved an average Columbic efficiency of 99.4% and a capacity retention of 89.8%. This novel fabrication strategy for Tri-CPE structures has potential applications in the preparation of highly safe high-voltage cathodes for solid-state LMBs.
In an effort to minimize the usage of non-renewable materials and to enhance the functionality of the renewable materials, we have developed thin metal oxide coated porous carbon derived from a highly abundant non-edible bio resource, i.e., palm kernel shell, using a one-step activation-coating procedure and demonstrated their superiority as a supercapacitive energy storage electrode. In a typical experiment, an optimized composition contained ~10 wt% of Mn2O3 on activated carbon (AC); a supercapacitor electrode fabricated using this electrode showed higher rate capability and more than twice specific capacitance than pure carbon electrode and could be cycled over 5000 cycles without any appreciable capacity loss in 1 M Na2SO4 electrolyte. A symmetric supercapacitor prototype developed using the optimum electrode showed nearly four times higher energy density than the pure carbon owing to the enhancements in voltage window and capacitance. A lithium ion capacitor fabricated in half-cell configuration using 1 M LiPF6 electrolyte showed larger voltage window, superior capacitance and rate capability in the ~10 wt% Mn2O3 @AC than the pure analogue. These results demonstrate that the current protocol allows fabrication of superior charge storing electrodes using renewable materials functionalized by minimum quantity of earthborn materials.
To reduce surface contamination and increase battery life, MoO3 nanoparticles were coated with a high-voltage (5 V) LiNi0.5Mn1.5O4 cathode material by in-situ method during the high-temperature annealing process. To avoid charging by more than 5 V, we also developed a system based on anode-limited full-cell with a negative/positive electrode (N/P) ratio of 0.9. The pristine LiNi0.5Mn1.5O4 was initially prepared by high-energy ball-mill with a solid-state reaction, followed by a precipitation reaction with a molybdenum precursor for the MoO3 coating. The typical structural and electrochemical behaviors of the materials were clearly investigated and reported. The results revealed that a sample of 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode exhibited an optimal electrochemical activity, indicating that the MoO3 nanoparticle coating layers considerably enhanced the high-rate charge-discharge profiles and cycle life performance of LiNi0.5Mn1.5O4 with a negligible capacity decay. The 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode could achieve high specific discharge capacities of 131 and 124 mAh g-1 at the rates of 1 and 10 C, respectively. In particular, the 2 wt.% MoO3-coated LiNi0.5Mn1.5O4 electrode retained its specific capacity (87 mAh g-1) of 80.1% after 500 cycles at a rate of 10 C. The Li4Ti5O12/LiNi0.5Mn1.5O4 full cell based on the electrochemical-cell (EL-cell) configuration was successfully assembled and tested, exhibiting excellent cycling retention of 93.4% at a 1 C rate for 100 cycles. The results suggest that the MoO3 nano-coating layer could effectively reduce side reactions at the interface of the LiNi0.5Mn1.5O4 cathode and the electrolyte, thus improving the electrochemical performance of the battery system.
A novel scalable Taylor-Couette reactor (TCR) synthesis method was employed to prepare Ta-modified LiNi0.92Co0.04Mn0.04O2 (T-NCM92) with different Ta contents. Through experiments and density functional theory (DFT) calculations, the phase and microstructure of Ta-modified NCM92 were analyzed, showing that Ta provides a bifunctional (doping and coating at one time) effect on LiNi0.92Co0.04Mn0.04O2 cathode material through a one-step synthesis process via a controlling suitable amount of Ta and Li-salt. Ta doping allows the tailoring of the microstructure, orientation, and morphology of the primary NCM92 particles, resulting in a needle-like shape with fine structures that considerably enhance Li+ ion diffusion and electrochemical charge/discharge stability. The Ta-based surface-coating layer effectively prevented microcrack formation and inhibited electrolyte decomposition and surface-side reactions during cycling, thereby significantly improving the electrochemical performance and long-term cycling stability of NCM92 cathodes. Our as-prepared NCM92 modified with 0.2 mol% Ta (i.e., T2-NCM92) exhibits outstanding cyclability, retaining 84.5 % capacity at 4.3 V, 78.3 % at 4.5 V, and 67.6 % at 45 ℃ after 200 cycles at 1C. Even under high-rate conditions (10C), T2-NCM92 demonstrated a remarkable capacity retention of 66.9 % after 100 cycles, with an initial discharge capacity of 157.6 mAh g-1. Thus, the Ta modification of Ni-rich NCM92 materials is a promising option for optimizing NCM cathode materials and enabling their use in real-world electric vehicle (EV) applications.
Due to the poor thermal stability of conventional separators, lithium-ion batteries require a suitable separator to maintain system safety for long-term cycling performance. It must have high porosity, superior electrolyte uptake ability, and good ion-conducting properties even at high temperatures. In this work, we demonstrate a novel composite membrane based on sandwiching of zeolitic imidazole frameworks-67 decorated cellulose acetate nanofibers (ZIF-67@CA) with electrospun poly(vinyl alcohol)/melamine (denoted as PVAM) nonwoven membranes. The as-prepared sandwich-type membranes are called PVAM/x%ZIF-67@CA/PVAM. The middle layer of composite membranes is primarily filled with different weight percentages of ZIF-67 nanoparticles (x = 5, 15, and 25 wt%), which both reduces the non-uniform porous structure of CA and increases its thermal stability. Therefore, our sandwich-type PVAM/x%ZIF-67@CA/PVAM membrane exhibits a higher thermal shrinkage effect at 200 °C than the commercial polyethylene (PE) separator. Due to its high electrolyte uptake (646.8%) and porosity (85.2%), PVAM/15%ZIF-67@CA/PVAM membrane achieved high ionic conductivity of 1.46 × 10-3 S cm-1 at 70 °C, as compared to the commercial PE separator (ca. 6.01 × 10-4 S cm-1 at 70 °C). Besides, the cell with PVAM/15%ZIF-67@CA/PVAM membrane shows an excellent discharge capacity of about 167.5 mAh g-1after 100 cycles at a 1C rate with a capacity retention of 90.3%. The ZIF-67 fillers in our sandwich-type composite membrane strongly attract anions (PF6-) through Lewis' acid-base interaction, allowing uniform Li+ ion transport and suppressing Li dendrites. As a result, we found that the PVAM/15%ZIF-67@CA/PVAM composite nonwoven membrane is applicable to high-power, high-safety lithium-ion battery systems that can be used in electric vehicles (EVs).
Current commercial separators used in lithium-ion batteries have inherent flaws, especially poor thermal stability, which pose substantial safety risks. This study introduces a high-safety composite membrane made from electrospun poly(vinyl alcohol)-melamine (PVAM) and polyvinylidene fluoride (PVDF) polymer solutions via a dip coating method, designed for high-voltage battery systems. The poly(vinyl alcohol) and melamine components enhance battery safety, while the PVDF coating improves lithium-ion conductivity. The dip-coated PVDF/Esp-PVAM composite separators were evaluated for electrolyte uptake, contact angle, thermal stability, porosity, electrochemical stability and ionic conductivity. Notably, our Dip 1 % PVDF@Esp-PVAM composite separator exhibited excellent wettability and a lithium-ion conductivity of approximately 7.75 × 10⁻⁴ S cm⁻1 at room temperature. These separators outperformed conventional PE separators in half-cells with Ni-rich NCM811 cathodes, showing exceptional cycling stability with 93.4 % capacity retention after 100 cycles at 1C/1C, as compared to 84.8 % for PE separators. Our Dip 1 % PVDF@Esp-PVAM composite separator demonstrates significant potential for enhancing the long-term durability and high-rate performance of lithium-ion batteries, making it a promising option for long-term energy storage applications.