Long-lifetime Operation Research Articles

Towards net-zero smart system: An power synergy management approach of hydrogen and battery hybrid system with hydrogen safety consideration

The building system is one of key energy consumption sector in the market, and low-carbon building will make a significant contribution for the worldwide carbon emission reduction. The multiple energy systems including renewable generations, hydrogen energy and energy storage is the perspective answer to the net-zero building system. However, the research gap lies in the synergy power management among the renewable, flexible loads, batteries and hydrogen energy systems, and at the same time, taking the unique characteristic of different energy sectors into account by power managing. This paper proposed the power management approach based on the game theory, by which, the different characteristics of the energy players are described via creating the competing relationship against net-zero emission objective so that to achieve the power synergy. Under the proposed power management method, the hydrogen and battery hybrid system including the fuel cell, electrolyzer and battery is designed and investigated as to unlock the power management regions and control constraints within the building system. Particularly, for the hydrogen system within the hybrid system, the safe and long-lifetime operation is considered respectively by high-efficiency and pressure constraints within the power management. Simulation results show that, providing the same energy storage services for the building system, the fuel cell with the proposed power management method sustains for 9.9 years, much longer than that of equivalent consumption minimization (4.98), model predictive control (4.61) and rule-based method (7.69). Moreover, the maximum tank temperature of the hydrogen tank is reduced by 3.4 K and 2.9 K compared with consumption minimization strategy and model predictive control. Also, the real-time of the proposed power management is verified by a scaled-down experiment platform.

Characterization and Verification of Eddy-Current Position Sensing for Magnetic Levitation

Magnetically levitated drives are compelling in applications, where the long-lifetime operation or process chamber encapsulation is a requirement. To exploit these advantages, contactless position sensors are needed to estimate the position of the rotor. Off-the-market sensor technologies render high-performance magnetic levitation possible, yet their system integration may be challenging if a drive must be designed to fit existing sensor technology or bulky probes. In this work, a position-estimation system based on Eddy-current generation is proposed. Two integrated circuits (or only one for less time-critical applications) excite a two-axis differential array of four miniature coils that can resolve positions in the 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^0$</tex-math></inline-formula> <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 range. Coupled to a microcontroller, this system can sample the position of an electrically conductive target—in this study, the permanent magnet rotor of a magnetically levitated drive—with frequencies of over 3.5 kHz. This position estimation setup enables the successful levitation of two miniature bearingless disc drives and offers potential toward rotatory speeds in the 20 kr/min range.

Ultra-Stable, Ultra-Long-Lifespan and Ultra-High-Rate Na-ion Batteries Using Small-Molecule Organic Cathodes

Molecule-aggregation organic electrodes in principle possess the “single-molecule-energy-storage” capability for metal-ion rechargeable batteries. Besides dissolution issue, the effect of possible solvent co-intercalation in liquid electrolytes also devalues the true performance of organic electrodes due to the weak Van der Waals forces among organic molecules. Herein, a small-molecule organic cathode called [N,N’-bis(2-anthraquinone)]-perylene-3,4,9,10-tetracarboxydiimide (PTCDI-DAQ, 200 mAh g−1) can deliver the unprecedented results in sodium-ion batteries (SIBs) by carefully choosing high-concentration electrolytes, which can offer more free sodium ions and decrease the solvent co-intercalation effect. Consequently, PTCDI-DAQ can deliver an ultra-stable capacity above 153 mAh g−1 during a long-lifetime operation test in half cells (10 months at least). In full cells, the resulting PTCDI-DAQ II Na3Bi SIBs can deliver a peak discharge capacity of 206 mAh g−1cathode with an average voltage of 1.2 V, running with no capacity decay over 4 months. Meanwhile, our PTCDI-DAQ II Na3Bi SIBs can re-store a world record of 70% capacity retention (142 mAh g−1cathode) at 20 A g−1cathode (100 C). To the best of our knowledge, PTCDI-DAQ can currently represent the best organic cathode for SIBs in the world; and the integrated performance of our PTCDI-DAQ II Na3Bi SIBs can compete with the best SIBs reported to date.

Ultra-Stable, Ultra-Long-Lifespan and Ultra-High-Rate Na-Ion Batteries Using Small-Molecule Organic Cathodes

Molecule-aggregation organic electrodes in principle possess the “single-molecule-energy-storage” capability for metal-ion rechargeable batteries. Besides dissolution issue, the effect of possible solvent co-intercalation in liquid electrolytes also devalues the true performance of organic electrodes due to the weak Van der Waals forces among organic molecules. Herein, a small-molecule organic cathode called [N,N’-bis(2-anthraquinone)]-perylene-3,4,9,10-tetracarboxydiimide (PTCDI-DAQ, 200 mAh g-1) can deliver the unprecedented results in sodium-ion batteries (SIBs) by carefully choosing high-concentration electrolytes, which can offer more free sodium ions and decrease the solvent co-intercalation effect. Consequently, PTCDI-DAQ can deliver an ultra-stable capacity above 173 mAh g-1 during a long-lifetime operation test in half cells (6 months at least). In full cells, the resulting PTCDI-DAQ II Na3Bi SIBs can deliver a peak discharge capacity of 206 mAh g-1cathode with an average voltage of 1.2 V, running with no capacity decay over 4 months. Meanwhile, our PTCDI-DAQ II Na3Bi SIBs can re-store a world record of 70% capacity retention (142 mAh g-1cathode) at 20 A g-1cathode (100 C). To the best of our knowledge, PTCDI-DAQ can currently represent the best organic cathode for SIBs in the world; and the integrated performance of our PTCDI-DAQ II Na3Bi SIBs can compete with the best SIBs reported to date.small-molecule organic cathodes; ultra-stability; long lifespan; high rate; Na-ion batteries

Flexible, Temperature-Resistant, and Fatigue-Free Ferroelectric Memory Based on Bi(Fe0.93Mn0.05Ti0.02)O3 Thin Film.

A recent hot-spot topic for flexible and wearable devices involves high-performance nonvolatile ferroelectric memories operating under compressive or tensile mechanical deformations. This work presents the direct fabrication of a flexible (Mn,Ti)-codoped multiferroic BiFeO3 film capacitor with Pt bottom and Au top electrodes on mica substrate. The fabricated polycrystalline Bi(Fe0.93Mn0.05Ti0.02)O3 film on mica exhibits superior ferroelectric switching behavior with robust saturated polarization ( Ps ∼ 93 μC/cm2) and remanent polarization ( Pr ∼ 66 μC/cm2) and excellent frequency stability (1-50 kHz) and temperature resistance (25-200 °C), as well as reliable long-lifetime operation. More saliently, it can be safely bent to a small radius of curvature, as low as 2 mm, or go through repeated compressive/tensile mechanical flexing for 103 bending times at 4 mm radius without any obvious deterioration in polarization, retention time at 105 s, or fatigue resistance after 109 switching cycles. These findings demonstrate a novel route to designing flexible BiFeO3-based ferroelectric memories for information storage and data processing, with promising applications in next-generation smart electronics.

A Long-Lifetime Plasmatron for Use in Medicine

We report here studies of the properties of a new type of plasmatron with long-lifetime operation and an ultrapure plasma jet investigated using emission spectroscopy, thermal imaging, and chemical sparging. Results of measurements of the concentrations of the chemical radicals NO and NO2 and the distribution of the gas temperature close to the plasma jet, which determines the potential for using the plasmatron in medicine, are reported.

Sodium Ion Diffusion and Voltage Trends in Phosphates Na4M3(PO4)2P2O7 (M = Fe, Mn, Co, Ni) for Possible High-Rate Cathodes

Polyanionic phosphates have the potential to act as low-cost cathodes and stable framework materials for Na ion batteries. The mixed phosphates Na4M3(PO4)2P2O7 (M = Fe, Mn, Co, Ni) are a fascinating new class of materials recently reported to be attractive Na ion cathodes which display low-volume changes upon cycling, indicative of long-lifetime operation. Key issues surrounding intrinsic defects, Na ion migration mechanisms, and voltage trends have been investigated through a combination of atomistic energy minimization, molecular dynamics (MD), and density functional theory simulations. For all compositions, the most energetically favorable defect is calculated to be the Na/M antisite pair. MD simulations suggest Na+ diffusion extends across a 3D network of migration pathways with an activation barrier of 0.20–0.24 eV, and diffusion coefficients (DNa) of 10–10–10–11 cm2 s–1 at 325 K, suggesting good rate capability. The voltage trends indicate that doping the Fe-based cathode with Ni can significantly i...

A high-voltage gaseous switch triggered by a corona discharge for long-lifetime operation

A high-voltage gaseous-switch triggering method based on a capacitively coupled (pulsed corona) discharge is described. The method enables the single closure discharges of the switch to be distributed over a large area of the electrodes' surface, yielding a relatively low erosion rate. Therefore, long-lifetime operation of the switch without maintenance is obtained. The switch was tested by discharging a 7.5 nF capacitor at repetition frequencies up to 50 Hz. The maximum voltage was 17 kV with a current peak of about 6 kA.

Room-temperature-stable LiF:F_3^+ color-center laser with a two-mirror cavity

A reliable room-temperature-operated, pulsed LiF:(3)(+) color-center laser with a two-mirror cavity has been constructed. This laser is useful as a tunable, green, coherent light source. The laser has shown a long-lifetime operation and remarkable amplitude stability by pumping with a dye laser. The laser light has a peak at 543 nm. The slope efficiency is approximately 2%, and the pump threshold is approximately 75 mW.