Solid-state Storage Devices Research Articles

Numerical study on hydrogen desorption performance of a new MgH2 solid-state hydrogen storage device

To explore the factors affecting the hydrogen evolution performance of a new MgH2 solid-state hydrogen storage heat exchanger, this paper designs the MgH2 solid-state hydrogen storage device. The study numerically investigates the influence of operating parameters and structural parameters on the hydrogen release reaction. The results demonstrate that the hydrogen desorption rate increases as the pressure decreases from 0.3 MPa to 0.1 MPa. Moreover, the hydrogen evolution reaction rate significantly rises with an increase in the inlet temperature of the heat transfer fluid (HTF) from 600 K to 700 K. Similarly, the rate of hydrogen evolution reaction increases with an increase in the flow rate of the HTF from 0.5 m/s to 1.25 m/s. The hydrogen evolution reaction time can be notably reduced by increasing the thickness of the annular HTF layer. Compared to no annular fluid layer, the completion time of the hydrogen desorption reaction is shortened by 558 s with a 5 mm thickness. The arrangement of heat exchanger pipes plays a crucial role in the hydrogen evolution reaction, and thus a comprehensive index M is defined to evaluate its influence. A higher M value indicates slower hydrogen release efficiency of the device. By optimizing the operating conditions, the hydrogen desorption time can be shortened by 93.4 %.

A parametric study on hydrogen storage in AB5 hydride alloys: Heat and mass transfer, thermodynamics, and design

The design of heat exchangers plays an important role in the performance of solid-state hydrogen storage devices. In this study, three different designs of hydrogen storage devices were investigated, incorporating phase change material (PCM), specifically, RT25HC into their walls in various shapes. A mathematical model, validated using previous experimental data, was employed to calculate heat and mass transfer and determine the reaction time period. The calculations were conducted using ANSYS Fluent, with a constant hydrogen supply pressure of 10 bars and a temperature of 295 K. The absorption properties of the storage reactor were investigated through various parameters such as liquid fraction, hydrogen concentration, and natural convection heat transfer coefficients. Results showed that the geometric structure and PCM distribution significantly impacted the performance of the hydrogen storage devices. Design 1, with a centralized PCM distribution, demonstrated moderate heat transfer rates and a longer reaction time. Design 2, featuring a more distributed PCM layout, improved heat transfer rates and reduced hydrogen kinetics time by 40%. Design 3, which optimized the geometric structure with advanced PCM shapes, achieved the highest heat transfer rates and improved hydrogen kinetics time by 50%. This design also enabled the storage of thermal energy at a high density, ranging from 10.2 J/g to approximately 190.5 J/g. The study provides critical information on the design of efficient solid hydrogen storage processes. The findings suggest significant potential for improved performance in industrial applications such as electric vehicles and domestic energy supply. The high efficiency of the large-scale reactor is due to its well-designed system, which effectively converts chemical energy into thermal energy. Optimizing the reactor geometry and PCM distribution is crucial for achieving superior hydrogen storage and retrieval performance.

Ultrasound-assisted synthesis of Dy2Mo3O12-Dy2O3 nanostructures for enhanced electrochemical hydrogen storage

Among the major challenges facing the hydrogen economy is the issue of hydrogen storage. In terms of "future energy needs", electrochemical hydrogen storage in solid-state materials is an accepted perspective that could mitigate the discontinuation of primary energy sources. In this study, we demonstrate the electrochemical properties of a complex metal oxide that contains the molybdate group, Dy2Mo3O12. Wet-chemical synthesis of nanostructured Dy2Mo3O12 is primarily carried out using ultrasound-assisted wet-chemical methods in the presence of a variety of surfactants. The structural and morphological observations of the samples confirm a pure and highly crystalline structure obtained in the presence of CTAB surfactant at 900 °C and 30 min of sonication, with an average crystalline size of 29 nm. Based on the FTIR spectrum of this sample, it can be concluded that there are significant absorptions indicating the formation of oxygen-metal bonds. The specific surface area and pore volume of the selected sample are 4.543 m2/g and 0.0284 cm3/g, respectively, demonstrating its porous structure. Electrochemical studies of this sample at various temperatures have revealed an enhanced discharge capacity (5100 mAh/g at 65 °C) with a capacity retention rate of 97%. Based on these findings, mixed metal oxides containing at least one active charge transfer species (Red./Ox.) are suitable for use in solid-state hydrogen storage devices.

Optimization design of solid-state hydrogen storage device for fuel cell forklift

Solid-state hydrogen storage device using metal hydride have enormous advantages for fuel cell forklifts. In addition to high volume hydrogen storage density, the solid-state hydrogen storage device can also be used as a counterweight for the forklift. At the same time, the solid-state storage device has low hydrogen storage pressure and safety, and the fuel (H2) refueling is convenient and low-cost. In this paper, a two-dimensional heat and mass transfer numerical model has been developed to predicting the performance of the metal hydride tank filled with Ti0.9Zr0.1Cr0.35Mn1.4V0.2Fe0.05 alloy. The validity of this numerical model was tested by comparison with the experimental data of the metal hydride hydrogen storage tank with a hydrogen capacity of 1 kg, achieving a good agreement between all the data. And a solid-state hydrogen storage device with an effective hydrogen capacity of 1.5 kg is optimally designed for 3.5 T fuel cell forklift. The completion rate of hydrogen refueling in the solid-state hydrogen storage device will reach 97.6 % within 30 min, and continuously discharging over 1.5 kg H2 under flow rates of 150 SL/min and 250 SL/min. The optimized solid-state hydrogen storage device was integrated in a power module for 3.5 T fuel cell forklift which allows uninterrupted operation for at least 6 h 8 min under rated operation.

Experimental and theoretical validation of the solid-state heat storage device using the latent heat of martensitic transformation in shape memory alloy

Experimental and theoretical validation of the solid-state heat storage device using the latent heat of martensitic transformation in shape memory alloy

Comparison, advancement, and performance evaluation of heat exchanger assembly in solid-state hydrogen storage device

Despite myriads of mathematical and experimental studies using various heat exchanger-metal hydride assemblies, an adept comparison of reactors on standard performance defining parameters, i.e., reactor weight, external energy utilization, and alloy material, are not studied or reported for industrial storage containers and onboard applications. This lacuna is a critical barrier in developing efficacious hydrogen storage reactors for various applications. This article chronicles the 3-D design and optimization of three basic heat exchanger setups of solid-state hydrogen storage systems (shell and tube, spiral tube, and tubular) on critical parameters. For 5 kg LaNi5, a tubular design with small tube diameters has resulted in a shorter reaction time (120 s) for 90% saturation at 303 K and 15 bar inlet conditions; however, the reactor's gravimetric density was exceptionally high. In contrast, the reactor with three spiral tubes accomplished an exemplary reaction rate at a reasonable gravimetric density. This spiral arrangement became the base for developing a novel reactor that integrated heat pipes to reduce the sorption time. The proposed design achieved a specific output energy rate of 527 W/kg for 90% saturation in 366 s at a supply pressure of 15 bar, which is 23.7% higher than the reactor without heat pipes.

Performance and energy efficiency of a solid-state hydrogen storage system: An experimental study on La0.7Ce0.1Ca0.3Ni5

This study presents an experimental investigation conducted on an annular porous metal hydride reactor equipped with radial fins. The reactor was filled with 9 kg of La0.7Ce0.1Ca0.3Ni5, and water was considered as heat transfer fluid. The absorption characteristics were studied under different supply pressures (5–20 bar) and desorption characteristics under different inlet temperatures of heat transfer fluid (30–50 °C). An energy efficiency based on the higher heating value of hydrogen was evaluated for the developed solid-state hydrogen storage device. Further, the effect of pre-sensible heating on desorption performance and energy efficiency was analyzed. Finally, the experimental results were compared with the extensively studied LaNi5 alloy. The results showed that the alloy exhibited a constant desorption rate despite slower desorption kinetics. The energy efficiency of the developed system was found to be 76.76%. The comparison results showed that La0.7Ce0.1Ca0.3Ni5 exhibited higher storage capacity than LaNi5 after 20 cycles and approximately similar absorption and desorption rates. The desorption process without pre-sensible heating was more efficient and reduced overall desorption time by 46.5% than the desorption with pre-sensible heating. However, the desorption process without pre-sensible heating has not significantly affected the energy efficiency.

Latent heat storage of Nickel Titanium shape memory alloys and its application to solid-state heat storage device

Nickel Titanium shape memory alloy was proposed for heat storage material. When the shape memory alloy is in contact with a heat source, the heat flow from the heat source to the alloy was enhanced by the latent heat associated with the reverse martensitic transformation of shape memory alloy, and vice versa. This study performed both theoretical and computational analyses. First, the enthalpy curve in the temperature range of martensitic transformation was determined from the DSC curves obtained in experiment, which can describe the emission/absorption of latent heat during the martensitic transformation as the function of temperature. Next, a metal matrix composite of NiTi shape memory wires embedded in aluminum block was designed and the heat transfer with a heat source was observed by three-dimension finite element heat conduction analysis with ANSYS. We focused on the effects of the configuration of SMA wires and the heat resistance between the wire and aluminum matrix on the performance of the heat storage.

Parallel Computation in the Racetrack Memory

Racetrack memories are promising candidates for next-generation solid-state storage devices. Various racetrack memories have been proposed in the literature, skyrmion based or domain wall based. However, none of them show integrated computing capabilities. Here, we introduce a new domain wall based racetrack concept that can operate both as a memory and as a computing device. The computation is defined by changing locally the anisotropy of the film. Stray fields from nearby cells are exploited to implement reconfigurable logic gates. We demonstrate that the racetrack array can operate in parallel in every cell. This is achieved by an external out-of-plane Zeeman field applied to the array. As proof-of-principle, we verified the single computing cell and multiple connected cells operating in parallel by micromagnetic simulations. Logic NAND/NOR is implemented independently in every computing cell. This study provides the guidelines for the development and optimization of this family of logic gates.

Research on multi-physical field coupling of solid electrothermal storage unit

In recent years, the solid-state electro-thermal storage device has been connected to the power supply side of the power system for peak regulation by virtue of its high voltage and large capacity characteristics, which plays a positive role in the consumption of wind power, photovoltaic and other new energy. Based on the coupling effects of heat, current, electricity, magnetism, force and other physical fields in the equipment, this paper studies the optimal design of thermal storage structure. A multi-physical field and multi-criteria collaborative optimization design method was proposed to design the surface load of heating power, heat transfer channel of heat storage body, and porosity of body. Through the multi-field coupling numerical simulation and experiment verification, the thermal field, flow field, stress field, electric field and other changes are analyzed, and it is verified that the design method can effectively overcome the malpractice of low heat transfer rate temperature imbalance of thermal storage materials. The experimental results provide theoretical guidance for device design and engineering application.

Exploring Performance Characteristics of the Optane 3D Xpoint Storage Technology

Intel’s Optane solid-state nonvolatile storage device is constructed using their new 3D Xpoint technology. Although it is claimed that this technology can deliver substantial performance improvements compared to NAND-based storage systems, its performance characteristics have not been well studied. In this study, intensive experiments and measurements have been carried out to extract the intrinsic performance characteristics of the Optane SSD, including the basic I/O performance behavior, advanced interleaving technology, performance consistency under a highly intensive I/O workload, influence of unaligned request size, elimination of write-driven garbage collection, read disturb issues, and tail latency problem. The performance is compared to that of a conventional NAND SSD to indicate the performance difference of the Optane SSD in each scenario. In addition, by using TPC-H, a read-intensive benchmark, a database system’s performance has been studied on our target storage devices to quantify the potential benefits of the Optane SSD to a real application. Finally, the performance impact of hybrid Optane and NAND SSD storage systems on a database application has been investigated.

Real-time emulation and analysis of multiple NAND flash channels in solid-state storage device

NAND Flash is the most prevalent memory technology used today in data storage systems covering a wide range of applications, from consumer devices to high-end enterprise systems. In this work, we present a modular and versatile FPGA-based platform that achieves accurate emulation of multiple NAND Flash channels. The NAND Flash emulator is based on an expandable and reconfigurable architecture that can be used for developing and testing new NAND Flash controllers and for analysing the behaviour of existing NAND Flash controllers and/or host device drivers. The presented NAND Flash emulator is based on PCIe-based FPGA boards attached to a high-end server, supports standard memory interfaces, responds to all memory commands in proper time and has the capability to emulate memory space in the range of a few TBs. The NAND Flash emulator has been prototyped and tested, and experimental results demonstrate that all timing requirements are satisfied under maximum read/write workloads. The NAND Flash emulator also includes a hardware tracer unit that records information of all commands exchanged at the NAND Flash interfaces along with high resolution timestamps. The recorded information can be used to analyse higher level functions, like wear leveling and garbage collection, and combined with other software tools for analysing cognitive functions. Experimental results demonstrate the advantage of using this emulator for analysing how host device drivers implement wear leveling and garbage collection functions.

Efficient Methods for Trace Analysis Parallelization

Tracing provides a low-impact, high-resolution way to observe the execution of a system. As the amount of parallelism in traced systems increases, so does the data generated by the trace. Most trace analysis tools work in a single thread, which hinders their performance as the scale of data increases. In this paper, we explore parallelization as an approach to speedup system trace analysis. We propose a solution which uses the inherent aspects of the CTF trace format to create balanced and parallelizable workloads. Our solution takes into account key factors of parallelization, such as good load balancing, low synchronization overhead and an efficient resolution of data dependencies. We also propose an algorithm to detect and resolve data dependencies during trace analysis, with minimal locking and synchronization. Using this approach, we implement three different trace analysis programs: event counting, CPU usage analysis and I/O usage analysis, to assess the scalability in terms of parallel efficiency. The parallel implementations achieve parallel efficiency above 56% with 32 cores, which translates to a speedup of 18 times the serial speed, when running the parallel trace analyses and using trace data stored on consumer-grade solid state storage devices. We also show the scalability and potential of our approach by measuring the effect of future improvements to trace decoding on parallel efficiency.

All-Solid-State Supercapacitors Based on a Carbon-Filled Porous/Dense/Porous Layered Ceramic Electrolyte

Solid-state storage devices based on ceramic electrolytes have great potential because of their high security, long cycle life, and wide working temperature. In the present work, the three-dimensional structure of a carbon-filled porous/dense/porous layered ceramic electrolyte is designed for a solid-state supercapacitor. A single phase of Li1.3Al0.3Ti1.7P3O12 (LATP) is obtained by a one-step solid-state reaction using ammonium polyphosphate (APP) as a PO4 precursor. The densification of the LATP ceramic is improved by introducing sintering aids of LiMnPO4 (LMP). Porous/dense/porous layered ceramics were then fabricated by sintering the LATP/LATP-2%LMP/LATP pellet at 825°C. Carbon-filled layered ceramics show a large capacitance of 0.13 F cm−1 at a low scan rate of 2 mV s−1. The large capacitance for carbon-filled layered ceramics is due to the enhanced contact area between the electrode and solid electrolyte in the porous structure. The present supercapacitor also shows good cycling stability (∼91% of the initial capacitance after 600 cycles at a scan rate of 5 mV s−1).

A Novel Data Aggregation Preprocessing Algorithm in Flash Memory for Iot Based Power Grid Storage System

NAND flash memory has the advantages of strong shock resistance, low power consumption, non-volatility, and high performance, and it is gradually applied to embedded systems and enterprise servers, such as the IoT-based power grid storage system. Therefore, research on the flash translation layer strategy has become a popular trend for solid-state storage devices. The mapping granularity of different FTL policies is different in the methods of garbage collection. Furthermore, there is a problem of “write amplification” in the write operation of the flash memory device. This paper proposes a data aggregation preprocessing algorithm that can aggregate as many active pages as possible and reduce the proportion of write amplification. The algorithm is implemented and tested on the flash simulation platform FlashSim. The results indicate that our algorithm can effectively improve the performance of the IoT-based power grid storage system, reducing redundant write operations, the number of physical block erasures, the number of physical page read and write times, and the system response time, and extending the life of solid-state devices.

Synthesis and optoelectronic properties of an electrically stimulated phosphorescent iridium complex

In order to better describe and verify the mechanism of electrophosphor discoloration, an ionic iridium complex with different counterions is designed and synthesized. It is found that the luminescent properties of the phosphor not only show the concentration and acid / base induced phosphorescence, but also show the phosphorescence change induced by electrical stimulation. The hydrogen bond acceptor (-NH) is introduced into the ionic iridium complex to modulate the emission wavelength of the complex by different counterions. In order to further control the emission wavelength of the complexes, a series of ionic iridium complexes with different counterions are designed and synthesized by selecting the auxiliary ligands containing two hydrogen bond acceptors (-NH). It is proved that there is not only electrostatic interaction between the cations and counterions, but also interesting hydrogen bonds. In addition, because the hydrogen bond strength formed by complex anions and different counter anions is different, it can effectively control the photophysical properties of complexes and adjust the emission wavelength from 493 nm to 591 nm. In conclusion, the phosphorescence change induced by electric field can be realized by applying the electric field to change the hydrogen bonding intensity. At the same time, the construction of quasi solid-state information storage devices is beneficial to the development of phosphorescent materials in information optoelectronic devices.

Reliability and performance enhancements for SSD RAID

NAND based solid state storage devices are almost ubiquitously used in safety-critical embedded devices, and recent advances have demonstrated RAID architectures specific to solid state storage devices resulting in increased data reliability, with architectural enhancements to solve the age convergence problem. However, these techniques require devices to be taken off-line while components are replaced—consequently these devices are of limited use in hard real time systems. There are further real time issues in that the conventional architectures ignore other characteristics of solid state devices such as garbage collection and meta data management. In this paper we investigate techniques that support the replacement of aged devices in the array in such a way that we provide continuous system reliability. We also improve the performance overhead of the reconstruction process using a novel data migration policy. The techniques are implemented and tested in a trace-driven simulator, and results demonstrate that average I/O response time is improved by up to 39% with improvement by up to 45% in its standard deviation, overheads in terms of device replacement time are negligible, and read performance is improved by an average of 8%.

Exploiting Intracell Bit-Error Characteristics to Improve Min-Sum LDPC Decoding for MLC NAND Flash-Based Storage in Mobile Device

A multilevel per cell (MLC) technique significantly improves the storage density, but also poses serious data integrity challenge for NAND flash memory. This consequently makes the low-density parity-check (LDPC) code and the soft-decision memory sensing become indispensable in the next-generation flash-based solid-state storage devices. However, the use of LDPC codes inevitably increases memory read latency and, hence, degrades speed performance. Motivated by the observation of intracell unbalanced bit error probability and data dependence in the MLC NAND flash memory, this paper proposes two techniques, i.e., intracell data placement interleaving and intracell data dependence aware LDPC decoding, to efficiently improve the LDPC decoding throughput and energy efficiency for the MLC NAND flash-based storage in a mobile device. Experimental results show that, by exploiting the intracell bit-error characteristics, the proposed techniques together can improve the LDPC decoding throughput by up to 84.6% and reduce the energy consumption by up to 33.2% while only incurring less than 0.2% silicon area overhead.

Review on Physically Flexible Nonvolatile Memory for Internet of Everything Electronics

Solid-state memory is an essential component of the digital age. With advancements in healthcare technology and the Internet of Things (IoT), the demand for ultra-dense, ultra-low-power memory is increasing. In this review, we present a comprehensive perspective on the most notable approaches to the fabrication of physically flexible memory devices. With the future goal of replacing traditional mechanical hard disks with solid-state storage devices, a fully flexible electronic system will need two basic devices: transistors and nonvolatile memory. Transistors are used for logic operations and gating memory arrays, while nonvolatile memory (NVM) devices are required for storing information in the main memory and cache storage. Since the highest density of transistors and storage structures is manifested in memories, the focus of this review is flexible NVM. Flexible NVM components are discussed in terms of their functionality, performance metrics, and reliability aspects, all of which are critical components for NVM technology to be part of mainstream consumer electronics, IoT, and advanced healthcare devices. Finally, flexible NVMs are benchmarked and future prospects are provided.

Invited: Tethered Molecular Sorbents: Enabling Lithium-Sulfur Battery Cathodes

A rechargeable battery that employs sulfur at the cathode and a metal (e.g. Li, Na, Mg or Al) at the anode provides perhaps the most promising path to a solid-state electrochemical storage device capable of high charge storage capacity. It is now understood that the dissolution of long-chain lithium polysulfides (Li2Sx, 2 < x < 8) into the electrolyte and the shuttling of polysulfides between cathode and anode has hindered the development of Li-S battery[1].Researchers have proposed different methods to prevent polysulfide dissolution and shuttling in Li-S batteries. Many of the most successful approaches focus on physically restraining polysulfide dissolution by using barrier materials, including micro- and mesoporous carbon as capsules for sulfur[2], or by incorporating sulfur into carbon nanotubes[3] and graphene/graphene oxide sheets[4]. It is understood, however, that because the barrier to Li2Sx dissolution in the electrolyte is kinetic, polysulfides physically trapped in the meso- or nanopores of a carbon host will eventually leach into the electrolyte leading to premature cell failure.In our work, we have developed a novel class of molecular sorbents for sulfur cathodes, which take advantage of strong lithium-nitrogen and lithium-chlorine interactions to sequester lithium polysulfides in the cathode. Additionally, the sorbent species are designed with anchoring groups (silane) such that they can cross-link within the cathode and bind to the surface of carbon (Figure 1).Beginning with density-functional calculations of the structure and interactions of a generic lithium polysulfide species with nitrile and imidazolium containing molecules, we show that the Li2Sx entrapment by our method is of thermodynamic origin and persists via strong lithium-electrophile interactions. The interaction is also confirmed by FTIR, ICP-AES and other techniques.Application of the concept to lithium-sulfur batteries leads to cells with potential profiles (Figure 2) which show no noticeable changes even after 50 cycles, while the one without sorbent already show noticeable changes in peak positions and current amplitudes by the 10thcycle. As an illustration of the effectiveness of the tethered sorbents, it is found that as little as 2w% of a nitrile-rich molecular species can increase the storage capacity of the sulfur cathode from effectively 100 mAh/g to at least 750 mAh/g after 100 charge/discharge cycles at a rate of 1C.Our approach circumvents the need to apply coatings to the carbon or for thermal infusion of the sulfur into a porous carbon host. Preliminary thermodynamic analysis suggests that the method can also be used with oxygen-, chlorine-, fluorine-, and phosphorous-rich molecules. We expect that future results will be presented in the talk elaborating on the relative effectiveness of additives species based on each of these molecules for preventing polysulfide loss in lithium-sulfur battery. Reference [1] J. L. Wang, J. Yang, J. Y. Xie, N. X. Xu, Adv. Mater. 2002, 14, 963.[2] X. Ji, K. T. Lee, L. F. Nazar, Nat. Mater. 2009, 8,500.[3] G. Zheng, Y. Yang, J.J. Cha, S. S. Hong. Y. Cui, Nano Lett. 2011, 11, 4462.[4] L. Ji, M. Rao, L. Zheng, Y. Li, W. Duan, J. Guo, E. J. Cairns, Y. Zhang, J. Am. Chem. Soc. 2011,133, 18522.