Outstanding Safety Performance Research Articles

Droplet and solution contact assembled cobalt alginate for enhanced properties of ammonium perchlorate

Ammonium perchlorate (AP) needs to be combined with nano-metal oxides to improve its thermal decomposition performance when applied to propellant, but with reduced safety performance. Herein, inspired by the rapid gelation of sodium alginate (Na-A) in the presence of metal ions to produce well-dispersed metal oxides after calcination, a novel “droplet and solution contact assembly” (DSCA) method is proposed and applied to prepare spherical AP/cobalt alginate (Co-A) composites. In spherical composite, Co-A forms a three-dimensional network structure and AP particles are uniformly and tightly filled in the network structure of Co-A, exhibitng outstanding safety performance. During the thermal decomposition process of it, Co-A thermally decomposes into evenly dispersed nano-Co3O4 and solves the facilely gathering trouble of nano-Co3O4, further results in an enhanced catalytic effect in thermal decomposition. In addition, compared with conventionally used methods for the spherification of composites, such as spray drying and electrospray methods, the method provides simpler, safer preparation conditions without high-temperature or high-voltage, which can be applied for mass production. Moreover, the atomization method is improved by replacing traditional atomization instrument with a hand-held high-velocity air spray gun, reducing the cost of the experiment and improving the convenience of the experiment. This study offers a new perspective for the design and systhesis of spherical composites.

Elucidating the diffusion pathway of lithium ions in superionic halide solid electrolytes Li2+xHf1−xInxCl6 for all-solid-state lithium-metal based batteries

All-solid-state batteries (ASSBs) with inorganic solid-state-electrolytes (SSEs) have been regarded as the promising candidate for next-generation energy storage due to their high energy density and outstanding safety performance. However, the representative oxide and sulfide electrolytes suffer from low ionic conductivity and poor (electro)chemical stability, respectively. Herein, we report a series of new halide superionic conductors Li2+xHf1−xInxCl6 with high ionic conductivity up to 1.05 mS cm−1 at 30 °C that are simultaneously stable to high voltage. By means of the characterization techniques and bond-valence site energy (BVSE) calculation, insights into the effect of the phase transformation and underlying ionic transport mechanism by In substitution for Hf in Li2HfCl6 are provided. Importantly, with the increased amount of aliovalent substitution in Li2+xHf1−xInxCl6 microcrystal framework, a gradual structure evolution from trigonal to monoclinic phase has been observed, which is accompanied by the redistribution of Li-ions to generate two dimensionally (2D) preferable diffusion pathways through octahedral-tetrahedral-octahedral sites in In3+-substituted Li2HfCl6. Additionally, due to the oxidative stability of In-substituted Li2HfCl6, the bulk-type ASSBs with bare LiCoO2 deliver distinguished electrochemical performance.

Competitive Li+ Coordination in Ionogel Electrolytes for Enhanced Li-Ion Transport Kinetics.

Developing ionogel electrolytes based on ionic liquid instead of volatile liquid in gel polymer electrolytes is regarded to be effective to diminish safety concerns in terms of overheating and fire. Herein, a zwitterion-based copolymer matrix based on the copolymerization of trimethylolpropane ethoxylate triacrylate (ETPTA) and 2-methacryloyloxyethylphosphorylcholine (MPC, one typical zwitterion) is developed. It is shown that introducing zwitterions into ionogel electrolytes can effectively optimize local lithium-ion (Li+ ) coordination environment to improve Li+ transport kinetics. The interactions between Li+ and bis(trifluoromethanesulfonyl)imide (TFSI- )/MPC lead to the formation of Li+ coordination shell jointly occupied by MPC and TFSI- . Benefiting from the competitive Li+ attraction of TFSI- and MPC, the energy barrier of Li+ desolvation is sharply decreased and thus the room-temperature ionic conductivity can reach a value of 4.4×10-4 S cm-1 . Besides, the coulombic interaction between TFSI- and MPC can greatly decrease the reduction stability of TFSI- , boosting insitu derivation of LiF-enriched solid electrolyte interface layer on lithium metal surface. As expected, the assembled Li||LiFePO4 cells deliver a high reversible discharge capacity of 139 mAh g-1 at 0.5 C and good cycling stability. Besides, the pouch cells exhibit a steady open-circuit voltage and can operate normally under abuse testing (fold, cut), showing its outstanding safety performance.

Can automated driving prevent crashes with distracted Pedestrians? An exploration of motion planning at unsignalized Mid-block crosswalks

Pedestrian distraction may provoke severe difficulties in automated vehicle (AV) control, which may significantly affect the safety performance of AVs, especially at unsignalized mid-block crosswalks (UMCs). However, there is no available motion-planning model for AVs that considers the effect of pedestrian distraction on UMCs. This study aims to explore innovative approaches for safe and reasonable automated driving in response to distracted pedestrians with various speed profiles at UMCs. Based on two common model design concepts, two new models are established for AVs: a rule-based model that solves motion plans through a fixed calculation procedure incorporating several optimization models, and a learning-based model that replaces the deterministic optimization process with policy-gradient reinforcement learning. The developed models were assessed through simulation experiments in which pedestrian speed profiles were defined using empirical data from field surveys. The results reveal that the learning-based model has outstanding safety performance, whereas the rule-based model leads to remarkable safety problems. For distracted pedestrians with significant crossing-speed changes, rule-based AVs lead to a 5.1% probability of serious conflict and a 1.4% crash probability. The learning-based model is oversensitive to risk and always induces high braking rates, which results in unnecessary efficiency loss. To overcome this, a hybrid model based on the learning-based model was developed, which introduces a rule-based acceleration value to regularize the action space of the proposed learning-based model. The results indicate that the hybrid approach outperforms the other two models in preventing crash hazards from distracted pedestrians by employing appropriate braking behaviors. The high safety performance of the hybrid models can be attributed to the spontaneous slowing down of the vehicle that initiates before detecting pedestrians on UMCs. Although such a cautious driving pattern leads to extra delay, the time cost of the hybrid model is acceptable considering the significant improvements in ensuring pedestrian safety.

Preparation and characterisation of the NBC/CL-20/AP nanoenergetic composite materials

ABSTRACT In this study, a novel nitrated bacterial cellulose/2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/ammonium perchlorate nanoenergetic composite was successfully prepared by the sol–gel method and the freeze-drying technology. The structure and composition were characterised by means of scanning electron microscope, X-ray diffractometer and Fourier-transform infrared. The results demonstrated that the structure of the gel nanoparticles was granted with unique network cross-linked porous, wherein the hexaazaisowurtzitane and ammonium perchlorate nanoparticles were embedded and dispersed uniformly in the gel matrix. The thermal decomposition properties of composites were analysed by differential scanning calorimeter-thermogravimetric analysis, and the results revealed that the composites exhibited only two exothermal peaks which correspond to the nitrated bacterial cellulose/hexaazaisowurtzitane and ammonium perchlorate. In addition, the impact and friction sensitivities of composites were also performed and showed outstanding safety performance. Hence, this preparation strategy of nitrated bacterial cellulose-based nanocomposite energetic materials may provide promising application in high-performance and low-sensitivity propellants.

A long-life and safe lithiated graphite-selenium cell with competitive gravimetric and volumetric energy densities

Lithium-selenium (Li-Se) battery is a promising system with high theoretical gravimetric and volumetric energy densities, while its long-term cyclability is hard to realize, especially when a practical Se cathode with high Se content, high Se loading, and high density is employed. The main obstacles are the sluggish conversion kinetics of the dense Se cathodes and the continuous deterioration of the Li-metal anodes. Here, by introducing an acetonitrile (AN)-based electrolyte and replacing the Li electrode with a lithiated graphite, we successfully build a hybrid conversion-intercalation system using a high-content (80 wt%), decent-loading (3.0 mg cm−2), and low-porosity (44%) Se cathode. The as-designed lithiated graphite||Se (LG||Se) cell demonstrated a high Se utilization (97.4%), a long cycle life (3000 cycles), and an ultrahigh average Coulombic efficiency (99.98%). The cell also works well under lean-electrolyte (2 μL mg−1) condition and shows outstanding safety performance in the nail-penetrating test. The combination affords the competitive comprehensive performances, including high volumetric and gravimetric energy densities, long cycling life, and superb safety of the LG||Se cell. In addition, with a newly-designed three-electrode pouch cell, the lithiation of the graphite anodes could be done with an in-situ lithiation process, indicating the high potential of the as-proposed LG||Se cell for the practical applications.

Facile and Effective Positive Temperature Coefficient (PTC) Layer for Safer Lithium-Ion Batteries

With the popularization of lithium-ion battery propelled electric vehicles, the safety requirements of lithium-ion batteries are under immense scrutiny. Minimizing catastrophic cell failure events by developing improved safety features for lithium-ion batteries is an important endeavor. Herein, we report a novel, safe cathode configuration, achieved by sandwiching a positive temperature coefficient (PTC) material layer between the Al foil and active cathode material. The PTC layer (2–3 μm thick) was a composite of the carbon-coated LiFePO4(C-LFP), poly(vinylidene fluoride) (PVDF), and Super P. Due to the structural stability, good conductivity, and limited amount of C-LFP, the PTC layer maintained good structural integrity as a supporting layer between the Al current collector and active material layer. At high temperatures (>80 °C), the PTC effect was triggered in the protective layer by PVDF volume expansion, which effectively disrupted electron flow, leading to a dramatic increase in cathode resistance, thus preventing thermal runaway from occurring. Such a PTC layer-containing cell design not only shows outstanding safety performance during overheating scenarios but also has no degradation on cell performance. Furthermore, the PTC layer has good processability and is a convenient and practical material layer for commercial applications.

Safety evaluation of the flashing-driven natural circulation IPWR against Loss-of-Feedwater accident

IP100 reactor is a flashing-driven natural circulation IPWR in which the passive techniques are extensively utilized to acquire excellent safety performance. In this study, the safety performance of the IP100 reactor is evaluated against Loss-of-Feedwater accidents with different assumptions. The simulation model of the IP100 reactor along with its PRHRS is established by RELAP5/MOD3.4 code. Parametric analyses are conducted to reveal the effect of pressurization space volume, downcomer flow area and heat transfer area of the PRHR-HX on the reactor’s safety. The results show that the self-regulation mechanisms, including the self-pressurization mechanism and flashing-driven natural circulation, along with the PRHRS provide the IP100 an outstanding safety performance during the LOFW accident. A larger pressurization space volume and a smaller downcomer flow area offer a safer reactor performance. It is feasible to reduce the heat transfer area of the PRHR-HX for a compact configuration.

Study on the properties of Li2MnSiO4 as cathode material for lithium-ion batteries by sol-gel method

Li2MnSiO4 is considered a novel cathode material for lithium-ion batteries, due to its high theoretical capacity, outstanding safety performance, environmentally friendly nature, and low cost. In this study, Li2MnSiO4 was synthesized using sol-gel method as a potential high-performance cathode material for lithium-ion batteries (LIBs). The effects of the molar ratio of lauric acid, molar ratio of ethanol, and firing temperature and firing time on Li2MnSiO4 were systematically studied by orthogonal test. The optimum conditions for the synthesis of Li2MnSiO4 by sol-gel method were determined as follows: the ratio of lauric acid to Li2MnSiO4 was 3:2, the ratio of ethanol to Li2MnSiO4 was 3:1, the firing temperature was 650°°C, and the firing time was 10 h. The initial discharge capacity of Li2MnSiO4 as the positive electrode of the lithium-ion battery during the optimization process can reach 158.5 mAh/g within a wide voltage range of 1.5–4.5 V. The results show that the discharge capacity and cycle performance of Li2MnSiO4 can be improved by adding lauric acid and glycol.

Project characteristics indicating safety performance

Safety performance has been long discussed and assessed in order to ensure less harm identified and reduce accidents in construction projects. Practically, accident rate is one common used key performance indicator to indicate the on-site safety performance in construction projects worldwide. Theoretically, there were various indicators that developed for the assessment of the safety performance of construction projects. These indicators were derived from previous literatures and lack of potential linkage to the project performance of construction projects. Thus, it is worth to explore the project characteristics that identified in construction projects with outstanding safety performance. This study introduced the project characteristics that identified in the construction projects with outstanding safety performance. The project characteristics were firstly identified by the sate-of-the-practice review and verified by panels of experts through structured interview and questionnaire survey. In general, findings of literature and structured interview were consistent. A series of interviews were supplemented the literatures’ findings. There were totally 27 project characteristics that indicating outstanding safety performance of a construction project. Eighteen experts were participated in the questionnaire surveys to verify the importance levels of the proposed project characteristics. All experts agreed with project characteristics that indicating the safety performance of the construction projects. The most agreed project characteristics were good housekeeping, more support and commitment from senior management, clear understanding of construction work activities, and good planning of project execution. These are indicative to future development of project management practice and sustainable safety strategies in construction industry locally and globally.

The relationship between critical success factors, internal control and safety performance in the Malaysian manufacturing sector

There is a lack of conceptual models that explain the relationship among critical success factors, internal control and safety performance, especially in the manufacturing sector of Malaysia. The enforcement of internal control is linked to safety performance, and more research is needed to validate this relationship. Unless management identifies the critical success factors that have significant impact on safety and health, safety management systems such as OHSAS 18001 compliance auditing will have little impact on organizations’ safety performance. This study measured organizations’ perceptions on six critical success factors and enforcement of internal control by conducting a survey using a questionnaire given to 300 organizations in Malaysia’s manufacturing sector. Hundred and five organizations participated in this survey with a response rate of 35 percent. The reliability and validity of all the scales were found acceptable. The internal control was found to be the key mediator in the relationship between critical success factors and safety performance. Path analysis using Partial Least Squares (PLS) version 2.0M3 showed that Management Commitment, Employee Involvement, Safety Training and Government Regulation are related with Safety Performance through enforcement of internal control. This study emphasizes the need for enforcement of internal control to achieve outstanding safety performance.

Constructing Li3VO4 nanoparticles anchored on crumpled reduced graphene oxide for high-power lithium-ion batteries

Li3VO4 is considered to be one of the most promising anode materials for lithium-ion batteries (LIBs) because of its outstanding safety performance and energy density.

A Novel Digital Image Encryption Algorithm Based on Orbit Variation of Phase Diagram

Chaotic systems have been widely used in digital image encryption algorithms because of their characteristics of deterministic randomness, extreme sensitivity to initial values, etc. Although these chaos-based algorithms are good at performance in general, most of them are ineffective when confronting attacks such as the chosen plain image attack. So, this paper proposes a new digital image encryption algorithm based on orbit variation of phase diagram (AOVPD), which modifies the iterative sequence of chaotic system with the pixel values of plain image. Theoretical analysis proves that the proposed AOVPD has the ability to resist chosen plain image attack within two rounds of operation, while the existing algorithms could be cracked in the same situation. To be specific, AOVPD is effective when confronting various attacks including chosen plain image attack. Also, simulation results show that the proposed algorithm has an outstanding safety performance.

Elucidation of Reaction Mechanism at the Cathode/Electrolyte Interface in All-Solid-State Battery By Using Depth-Resolved X-Ray Absorption Spectroscopy

As one of the next-generation batteries, all-solid-state batteries have attracted a lot of attention due to their outstanding safety performance and energy density. However, their power performance are still far from traditional lithium ion batteries using liquid electrolyte, which is considered as a result of interfacial resistance existing between cathode and solid electrolyte. To overcome this inherent interfacial problem of all-solid-state batteries, there is an urgent need to understand the reaction mechanism at the cathode/electrolyte interface. As the origin of the interfacial resistance, so far there are three hypotheses have been proposed: the space-charge layer [1], the reaction product layer [2] and the mechanical structure change [3]. In this study, two types of LiCoO2 thin-film model electrodes with and without interface modification by using Li3PO4 interlayer were fabricated by pulsed laser deposition (PLD). The electrodes were applied for electrochemical measurement and depth resolved X-ray absorption spectroscopy (DR-XAS) measurement to investigate the reaction mechanism of interface between LiCoO2 cathode and Li2S-P2S5 solid electrolyte. In order to analyze the interfacial reaction, thin-film model electrode with LiCoO2 cathode and Li2S-P2S5 solid electrolyte was deposited on mirror-polished platinum substrate by PLD. A Li3PO4 interlayer was also deposited between cathode and solid electrolyte by PLD. Electrochemical measurements were performed by using liquid electrolyte (1M LiClO4 in propylene carbonate) and lithium metal anode. Cyclic voltammetry (CV) measurement was carried out from 3.2 V to 4.4 V at 0.1 mV/s. Electrochemical impedance spectroscopy (EIS) measurement was performed at 3.9 V, 4.0 V, 4.1 V, 4.2 V, 4.3 V and 4.4 V with a 30 mV amplitude during first charge and discharge cycle. The frequency range of EIS was limited from 10-2 to 106 Hz. DR-XAS measurements were conducted using the BL37XU beamline, SPring-8, Japan, with a two-dimensional pixel array detector, PILATUS (Dectris, Switzerland). Comparing to the thin-film electrode with Li3PO4 interlayer, the first cycle of CV curves of the electrode without Li3PO4 interlayer shows a current peak around 3.2 V, which is considered to come from the reaction between cathode and electrolyte. EIS measurements show that Li3PO4 interlayer can suppress the increase of interface resistant during charge and discharge, which means a more stable interface can be kept by interface modification. In order to make a more detailed observation of the interfacial structure, DR-XAS near edge structure of the electrodes are analyzed at Co K-edge. The energy shift around the interface in the electrodes with Li3PO4 interlayer is smaller than that of samples without Li3PO4 interlayer. These results indicate that valence changes of cobalt ions near cathode/solid electrolyte interface are suppressed by interface modification. The introducing of Li3PO4 interlayer reduces the inter-diffusion between cathode and solid electrolyte. The results of both electrochemical and DR-XAS measurements present that the reaction mechanism is the reaction product layer at cathode/electrolyte interface in all-solid-state battery using sulfide electrolyte. Reference [1] K. Takada, N. Ohta, L. Zhang, K. Fukuda, I. Sakaguchi, R. Ma, M. Osada, T. Sasaki , Solid State Ionics, 179 (2008) 1333. [2] A. Sakuda, A. Hayashi, M. Tatsumisago, Chem Mater, 22 (2010) 949. [3] K. Kishida, N. Wada, H. Adachi, K. Tanaka, H. Inui, C. Yada, Y. Iriyama, Z. Ogumi., Acta Materialia, 55 (2007) 4713. Acknowledgement This research was financially supported by the Japan Science and Technology Agency (JST), Advanced Low Carbon Technology Research and Development Program (ALCA), Specially Promoted Research for Innovative Next Generation Batteries (SPRING) Project.

X-Ray Absorption Spectroscopic Analysis of Li3PS4 Glass-Carbon Composite Cathodes for All-Solid-State Lithium Secondary Battery

All-solid-state lithium secondary batteries with sulfide inorganic solid electrolytes have attracted attention because of their outstanding safety performance. However, the practical capacity of cathodes for all-solid-state batteries is smaller than lithium-ion battery cathodes because the composite electrodes are contained by solid electrolyte powder. To increase the practical capacity of composite cathodes, the composite material of milling Li3PS4 solid electrolyte with acetylene black was examined as an active material.1 While the improved capacity of cathodes was reported, the reaction mechanism of this active material has not been clarified yet. In this study, we investigated the electronic structure change of Li3PS4-acetylene black composite electrodes during charge-discharge for sulfide all-solid-state lithium secondary battery. The 75Li2S-25P2S5 (mol %) glass used as solid electrolyte for all-solid-state cells was prepared by mechanical milling. The Li3PS4-acetylene black composite electrode was obtained by ball milling of the mixture of the Li3PS4 and acetylene black with the weight ratio of 70:30 at 370 rpm for 1 h. All-solid-state battery cells were fabricated as follows. The Li3PS4-AB composite electrode (5–6 mg) and the 75Li2S-25P2S5 glass (80 mg) were set in a polycarbonate tube (φ10 mm) and pressed together under 360 MPa. An indium foil with a thickness of 100 μm was then placed on the surface of the solid electrolyte side of the bilayer pellet as a counter-reference electrode. Electrochemical tests of the cells were conducted at a constant current density of 0.064 mA cm−2 at 25 °C in an Ar atmosphere. X-ray absorption spectroscopy (XAS) was carried out at the beamline BL-13 in the SR center, Ritsumeikan University. Charged or discharged Li3PS4-AB composite electrodes were transferred into the chamber for XAS measurements. XRD patterns of charged and discharged sample showed no new peaks and Raman spectra showed remained PS4 3- anions in charge-discharge process. XPS analysis showed that new S-S covalent bonds were detected after charge. From S K-edge XAS spectra, the peak top was shifted from 2471 eV to 2472 eV and the intensity of the peak increased during charging. The change of S K-edge XAS clearly indicates the electronic structure of sulfur largely contribute the redox reaction in Li3PS4-AB composite electrode. Moreover, the extended X-ray absorption fine structure analysis showed the formation of S-S bonds in the charge reaction. 2 Reference 1. Hakari, T., Nagao, M., Hayashi, A., and Tatsumisago, M.,J. Power Sources, 2015, 293, 721-725. 2. Cuisinier, M., Cabelguen, P.-E., Evers, S., He, G., Kolbeck, M., Garsuch, A., Bolin, T., Balasubramanian, M., and Nazar, L. F.,The Journal of Physical Chemistry Letters, 2013, 4(19), 3227-3232. Acknowledgement This research was financially supported by Advanced Low Carbon Technology Research and Development Program (ALCA).

Depth-Resolved X-Ray Absorption Spectroscopic Studies on Reaction Mechanism at the Cathode/Electrolyte Interface in All-Solid-State Battery

As one of the next-generation batteries, all-solid-state batteries have attracted attention due to their outstanding safety performance and energy density. However, their power performance are still far from the increasing demand of electric vehicles, which seems to be caused by the large interfacial resistance between cathode and solid electrolyte. To overcome the inherent interfacial problem of all-solid-state batteries, there is an urgent need to understand the reaction mechanism at the cathode/electrolyte interface. As the origin of the interfacial resistance, three hypotheses have been proposed: the space-charge layer [1], the reaction product [2] and the mechanical structure change [3]. In this study, we applied thin-film model electrode for electrochemical measurement and depth resolved X-ray absorption spectroscopy (DR-XAS) measurement to investigate the reaction mechanism of interface between LiCoO2 cathode and Li2S-P2S5 solid electrolyte with interface modification by using Li3PO4 interlayer. In order to analyze the interfacial reaction between cathode and electrolyte, thin-film model electrode with LiCoO2 cathode and Li2S-P2S5 solid electrolyte was deposited on mirror-polished platinum substrate by pulsed laser deposition (PLD). A Li3PO4 interlayer was also deposited between cathode and solid electrolyte by PLD. Electrochemical measurements were performed by using liquid electrolyte (1M LiClO4 in propylene carbonate) and lithium metal anode. Cyclic voltammetry measurement (CV) was carried out from 3.2 V to 4.4 V at 0.1 mV/s. EIS measurement was performed at 3.9 V, 4.0 V, 4.1 V, 4.2 V, 4.3 V and 4.4 V with a 30 mV amplitude. The frequency range of EIS was limited from 10-2 to 106 Hz. Depth-resolved XAS measurements were conducted using the BL37XU beamline, SPring-8, Japan, with a two-dimensional pixel array detector, PILATUS (Dectris, Switzerland). The first cycle of CV curves of the film without Li3PO4 interlayer shows a current peak around 3.2 V, which is considered to come from the reaction between cathode and electrolyte. EIS measurements show that the interfacial resistance of the films with Li3PO4 interlayer does not increase compared with the film without Li3PO4 interlayer. In order to discuss the interfacial structure, depth resolved X-ray near edge structure at Co K-edge is analyzed. The energy shift around the interface in the film with Li3PO4 interlayer is smaller than that of sample without Li3PO4 interlayer. These results indicate that valence changes of cobalt ions near cathode/solid electrolyte interface are suppressed by using Li3PO4 interlayer. The introducing of Li3PO4 interlayer reduces the inter-diffusion between cathode and solid electrolyte. Reference [1] K. Takada, N. Ohta, L. Zhang, K. Fukuda, I. Sakaguchi, R. Ma, M. Osada, T. Sasaki., Solid State Ionics, 179 (2008) 1333. [2] A. Sakuda, A. Hayashi, M. Tatsumisago., Chem Mater, 22 (2010) 949. [3] K. Kishida, N. Wada, H. Adachi, K. Tanaka, H. Inui, C. Yada, Y. Iriyama, Z. Ogumi., Acta Materialia, 55 (2007) 4713. Acknowledgement This research was financially supported by the Japan Science and Technology Agency (JST), Advanced Low Carbon Technology Research and Development Program (ALCA), Specially Promoted Research for Innovative Next Generation Batteries (SPRING) Project.

Electrochemical and safety performance of Li pre-doping free cell using tin-phosphate glass-silicon composite anode

The Li pre-doping free cells using tin-phosphate glass (GSPO)-silicon composite anodes and lithium-rich layered oxide (LR-NMC) cathode were developed, in which the irreversible capacity of the cathode was utilized in order to compensate that of the anode. The irreversible capacity was equalized to that of the cathode at a Si/(GSPO + Si) mass ratio, r, of 0.8. The cell using the composite anode of r = 0.8 displayed a discharge capacity of 187 mAh g−1 as the cathode capacity at 30 °C and the 0.1C-rate. The long cycle performance of over 100 charge–discharge cycles was achieved. The cells also showed an excellent high- and low-temperature performance and a good rate performance. A stable performance was observed for over 50 cycles at 60 °C and the 0.5C-rate, and a high capacity of ca. 100 mAh g−1 as the cathode capacity even at −20 °C and the 0.2C-rate. The cell could discharge even at the 10C-rate. Furthermore, the Li pre-doping free cell showed an outstanding safety performance during the nail penetration test. When the 1500 mAh cell using the composite anode was penetrated by a nail, no thermal runaway was observed during the test.

Recovering large Brownfield projects in distress

A large body of knowledge exists about how to plan and establish projects for success; from project management guidelines to staged gate-execution methodologies. Despite such prescriptive means to guarantee project success, the upstream oil and gas industry has a poor track record for delivering large projects. Little guidance exists on how to restore delivery assurance to partially executed projects in distress. Furthermore, recovery efforts for large brownfield projects, mid-way through their execution, are further complicated and highly constrained. Operators and contractors alike are understandably concerned about the high failure rate of projects, particularly as Australia competes for global capital in the final investment decision for a project’s development. Issues cover the full spectrum of safety, cost, schedule, start-up, and operability. Furthermore, unanticipated issues such as industrial relations, resourcing, project controls, estimate basis, and design changes all play a central role in why projects find themselves in distress. In a recent case study, a structured recovery approach restored delivery assurance to a $900 m upstream brownfield project. Despite the numerous challenges encountered during the recovery efforts, the project went on to deliver ahead of its revised cost and schedule commitment, while also achieving outstanding safety performance. The self-governance program was instrumental in restoring delivery performance through responsive decision making that was robust, repeatable and preserved free calendar time for early intervention on high value recovery issues. The journey of recovery also restored a fractured client and contractor relationship by fostering a project delivery environment that was highly collaborative.

Development of High-Capacity Li-Ion Batteries Using Phosphate-Based Materials and Their Safety Evaluation

The electrochemical properties and safety performance of the phosphate-based cells using a SnO-P2O5 glass (GSPO) anode and glass-ceramic LiFePO4 (GC-LFP) cathode were evaluated. The cell displayed an excellent performance over the wide temperature range of −20°C to 60°C. The laminated-type pouch cell with a capacity of 660 mAh using the GSPO anode and GC-LFP cathode had no thermal runaway during the nail penetration test, in which the internal short-circuit condition occurred only for a moment and then rapidly recovered, accompanied by an increasing nail internal temperature to 49°C and the cell surface temperatures to 29°C. The XRD measurement and Rietveld refinement revealed that the nail penetrated part had a lower tin-lithium alloy content than the other part away from the nail penetrated part, indicating that the GSPO anode must be deeply discharged locally in the internal short-circuit part due to the insulating of the GSPO. Thus, the GSPO anode is the key material to provide the outstanding safety performance. During the overcharge test, no punk and no fire were also observed, though the cell voltage rapidly increased from 10 V to 32 V, accompanied by an increasing cell surface temperature only to 110°C.

Subcontractor Partnering: I'll Believe It When I See It

During a recent construction project, a special principle-based partnering process was developed. At the beginning of the project, the general contractor and the subcontractors met, away from the jobsite, for one full day to review the scope of the project, the site conditions, and the safety requirements, and to begin developing trust and open communications. The most important challenge was breaking the pattern of low trust that is common between general contractors and subcontractors. Throughout the life of the project, the general contractor's management personnel and the subcontractor's site supervision met weekly, on-site, to assess progress and sustain open communications. As a result, the subcontractors were rewarded with consistency of performance, great gains in technical and construction management knowledge, outstanding safety performance, tangible financial results, repeat business, greater loyalty from their employees, a satisfied client, and tremendous pride in a job well done.