High Voltage Research Articles

Isolated p-Block Antimony Atoms Activated CuO@Co-CN Enable High Performances for Water Splitting and Zn-Air Batteries.

This study reports an effective strategy for designing 3D electrocatalyst via the deposition of ZIF67-derived Co-CN shell layer over CuO nanoarrays to form a CuO@Co-CN hybrid, followed by incorporation with p-block Sb single atoms (CuO@Co-CN/Sb) to obtain highly activated catalytic behaviors. Inheriting both the excellent intrinsic catalytic activity of the components and their synergy, the CuO@Co-CN/Sb material serves as a high-efficiency multifunctional catalyst for overall water splitting and zinc (Zn)-air batteries. The material yields a current density of 10 mAcm-2 at a low overpotential of 72 and 250mV for the hydrogen evolution reaction and oxygen evolution reaction, respectively. Furthermore, an electrolyzer based on CuO@Co-CN/Sb shows remarkable performance with a derived current density of 0.5 Acm-2 at low cell voltage of 2.67V and good stability for 50h continuous operation at a high current density of 0.5 Acm-2. Simultaneously, Zn-air battery using the CuO@Co-CN/Sb material as air cathode yields a high open circuit voltage of 1.455V and a discharge power density of 131.07 mWcm-2.

Regulated Li+ Solvation via Competitive Coordination Mechanism of Organic Cations for High Voltage and Fast Charging Lithium Metal Batteries.

Li+ solvation exerted a decisive effect on electrolyte physicochemical properties. Suitable tuning for Li+ solvation enabled batteries to achieve unexpected performance. Here, we introduced inert organic cations to compete with Li+ for combining electrolyte molecules to modulate Li+ coordination in the electrolyte. The relevance between the number of cationic sites in organic cations and the competitive solvation ability was explored. The organic cations with multiple cationic sites attracted solvent molecules and anions away from Li+ to form new solvated shell, improving the Li+ transport kinetics and desolvation process in electrolyte while enhancing electrolyte oxidation tolerance. Moreover, electrostatic shielding provided by organic cations and anion-derived robust SEI promoted uniform and rapid Li+ deposition on Li electrodes. With the positive effect of organic cations, Li||LiCoO2 (LCO) batteries showed high specific capacity (136.46 mAh g-1) at high charge/discharge rate (10 C). Furthermore, Li||LCO batteries exhibited good capacity retention (70% after 500 cycles) at 4.6 V charge cut-off voltage. This work provides fresh insights for the optimization of electrolytes and battery performance.

The Cathode-Electrolyte Interface Constructed with Antioxidant Ascorbic Acid Guides LNMO to Achieve Stable Cycling Under High Voltage Conditions.

LiNi0.5Mn1.5O4 (LNMO) is considered one of the most promising cathode materials for high-energy-density lithium-ion batteries (LIBs). However, free-radical-induced carbonate electrolyte decomposition is a key factor hindering the improvement of battery stability. Inspired by the antioxidative properties of ascorbic acid (AA) in scavenging free radicals, the addition of AA during the electrode fabrication process can effectively terminate free radical chain reactions within the cycling of LNMO. This action prevents severe electrolyte decomposition, thus stabilizing the cathode-electrolyte interface (CEI) and ultimately enhancing battery stability. The results demonstrate that LNMO||Li half-cell with the addition of AA show significantly improved cycling performance after 1000 cycles at 1 C, with a high capacity retention rate of 87.4%, surpassing the 43.6% retention rate achieved by batteries using PVDF alone as a binder. This work introduces an efficient and straightforward strategy for designing functional additives to stabilize phase interfaces, offering an economically efficient choice to enhance the electrochemical performance of the LNMO.

Organic Cathode Electrolyte Interphase Achieving 4.8 V LiCoO2.

Developing high-voltage electrolytes to stabilize LiCoO2 (LCO) cycling remains a challenge in lithium-ion batteries. Constructing a high-quality cathode electrolyte interface (CEI) is essential to mitigate adverse reactions at high voltages. However, conventional inorganic CEIs dominated by LiF have shown limited performance for high-voltage LCO. Here, we propose an ionic liquid electrolyte (ILE) with a high donor number additive, enabling Li//LCO cells to achieve a high cut-off voltage of 4.7 V/4.8 V and a high-capacity retention of 86.9%/74.2% after 100 cycles at 0.5 C. During this process, a groundbreaking phenomenon was discovered: the construction of a stable organic CEI rich in C-F bonds by the high donor number additive under high voltage. These strong polar C-F bonds exhibit excellent electrochemical inertness and film-forming properties, resulting in optimal passivation of the cathode. This organic C-F bond-dominated CEI significantly suppresses phase transitions, cobalt dissolution, and gas evolution in LCO at high voltage. Additionally, the 4.8 V-class Li//LiNi0.6Co0.2Mn0.2O2 and 4.95 V-class Li//LiNi0.5Mn1.5O4 cells also demonstrate outstanding cycling stability. Even at 60 °C, the ILE-constructed organic CEI maintains superior performance. Our findings highlight the potential of organic CEI to enhance high-voltage cathode stability, paving the way for more efficient lithium-ion batteries.

Advanced Balancing of High-Energy Lithium Ion Cells Comprising Lithium-Rich Layered Oxide and a-Si/CuSi Nanowire Using a Cathode Pre-Lithiation Additive

Abstract Advances in lithium-ion battery (LIB) research have strived for high-energy, safe, and sustainable materials. Li-rich Li1.2Ni0.2Mn0.6O2 (LRNM) cathodes have shown great promise with high voltages and excellent specific capacities. Obstacles preventing the viability and commercialization of LRNM are the initial capacity loss of roughly 30% and rapid voltage decay upon cycling. Herein, lithium oxalate (Li2C2O4) is investigated as a pre-lithiation additive to utilize the first-cycle lithium re-intercalation losses of LRNM to compensate the irreversible lithium consumption in graphite and high-capacity a-Si on copper silicide nanowire (a-Si/CuSi NW) anodes. Specifically, the decomposition process of Li2C2O4 as well as the interaction between the electrode components inside the cell are comprehensively examined. This concept allows us to extend the cycle life of graphite||LRNM cells at 1C from less than 500 cycles (142 mAh g-1, 78%) to more than 900 cycles (143 mAh g-1, 82%) before reaching the 80% capacity retention threshold. Finally, LRNM electrodes with a precisely balanced concentration of Li2C2O4 are prepared in order to compensate the high irreversible losses of a-Si/CuSi NW anodes, achieving a capacity retention of almost 50% with a remaining specific capacity of 82 mAh g-1 after 400 cycles in high-energy a-Si/CuSi NW||LRNM lithium-ion cells.

High Voltage Pulsed Radiofrequency Combined With Duloxetine on the Treatment of Glossopharyngeal Neuralgia.

The incidence of glossopharyngeal neuralgia (GPN) is low, but the pain of GPN is severe and seriously affects the patient's life. We report a case with GPN, who had pain relief after treatment with high-voltage pulsed radiofrequency (PRF) combined with duloxetine. This case indicates that high-voltage PRF combined with duloxetine may be an effective approach for reducing pain in patients with GPN, and duloxetine may have a potential advantage for patients with evoked pain.

Pulse Electrodeposition for Carbonate-Rich Deposits from Seawater

Seawater electrodeposition is gaining renewed interest in the context of sustainable development, both to build climate-resilient coastal infrastructure and for ocean-based decarbonization applications. Most of the applications benefit from CaCO3-rich deposits, but constant-voltage electrodeposition results in a mixture of CaCO3 and Mg(OH)2, especially at higher voltages where precipitation rates are more desirable. The use of pulse voltages can help control interfacial pH that dictates the precipitation reactions. Here, we explore the use of pulse electrodeposition as a function of pulse frequency and duty cycle to control deposit composition. The most CaCO3-rich deposits were obtained under 10 Hz frequency and 10% duty cycle conditions for the voltage window investigated (−0.8 V to −1.2 V vs. SCE). While pulsing the voltage increases the amount of CaCO3 deposited, the energy required per gram of CaCO3 is significantly higher (14.5×) when compared to the base case of applying a constant voltage of −0.8 V vs. SCE. Further optimization of pulse conditions, electrode materials, and system configuration could lead to finding parameters that result in exclusively carbonate deposits without compromising precipitation rates, which may prove to be more useful for corrosion protection, coastal infrastructure, and other applications in sustainable development.

Skeletal Rearrangement of Azo Compounds Enables Low-Potential, High-capacity Organic Anodes for Rechargeable Alkaline Batteries.

The widespread adoption of rechargeable alkaline batteries is plagued by the performance-limiting metal anodes, which are prone to (electro)chemical corrosion and raise environmental or economic concerns. Organic redox-active materials offer a potential solution, but they typically struggle with dissolution-induced degradation and insufficiently negative reduction potentials. Herein, we introduce benzo[c]cinnoline and its derivatives (collectively referred to as BCCs), a class of aromatic azo compounds with fused-ring structure, as promising organic anode materials. BCCs exhibit pronounced aromaticity and Brønsted basicity, conferring low reduction potentials and intrinsic insolubility in alkaline solutions. Paired with the industrially established nickel hydroxide cathode, these batteries deliver excellent capacity (297 mAh g-1 anode), high output voltage of 1.3 V, and extended cycle life (≈16000 cycles). Notably, they also operate efficiently at extremely low temperatures down to -85 °C with an 8 M KOH electrolyte. We further explore the feasibility for all-organic alkaline batteries by paring BCCs with the dihydro form of 4,4'-azopyridine, utilizing azo compounds for both anode and cathodes. This chemistry harnesses the unique properties of small organic molecules to enable all-organic batteries with high capacity of 236 mAh g-1, fast charging at 1200 C, and easy recyclability.

A New High Voltage Gain Common‐Ground Step‐Up DC‐DC Converter Integrating Coupled‐Inductors and Switched‐Capacitors

ABSTRACTThis study proposes a new high‐voltage gain quadratic‐structured common‐ground step‐up DC‐DC converter, integrating coupled‐inductors and switched‐capacitors. This configuration achieves a significant voltage gain without necessitating either a substantial duty cycle or an elevated turn ratio in the coupled‐inductors. A critical innovation is the embedding of the secondary windings of the coupled‐inductors into the switched‐capacitor cell, which not only enhances voltage gain but also effectively suppresses the inrush current typical in such cells. The converter's features include the successful recycling of energy from the leakage inductors; low voltage stress exerted on power switches; zero‐current switching (ZCS) turn‐on of the main switch; ZCS conditions for the diodes' turn‐off; reduced switching losses because of the application of a quasi‐resonant (QR) operation between the leakage inductors and middle capacitors; simultaneous operation of the power switches; continuous input current; a wide duty cycle range; and a common‐ground output–input connection. The operating principle, steady‐state analysis (CCM and DCM), design considerations, efficiency calculation, small‐signal modeling with controller design, and comparisons with other related converters are provided. Finally, experimental results from a 100‐ to 300‐W prototype with 20‐ to 30‐V input and 400‐V output are given to validate the proposed converter's theoretical analysis and feasibility.

Analysis and Design of Stacked Coupled Inductor Quadratic Boost Converter With a Lossless Snubber Cell

ABSTRACTThis paper introduces the stacked coupled inductor quadratic boost converter with an inductorless, passive lossless snubber cell suited for high step‐up applications with various microgrids. Some design constraints can be selected from the voltage gain techniques of the high step‐up converters to obtain the solution of improvement performance of converter. The proposed converter utilizes quadratic boost converter and coupled inductor to attain high voltage gain beyond the voltage multiplier/lift cells. In this proposed converter, the use of a stacked coupled inductor type introduces the leakage inductor to snubber cell as an inductor without using an extra inductor in proposed snubber cell. Thus, a regenerative snubber cell is used to achieve a high system efficiency. Compared with earlier counterparts, the solution of attaining a high voltage gain in the proposed converter and passive lossless snubber cell leads to an increase in the converter's performance, reliability, and robustness. The theoretical expectations are supported by simulations and verified by experimental results obtained by implementing a 300‐V, 120‐W prototype.

Experimental Study of the Flashover Process and the Leakage Current on the Surface of High Voltage Insulator Under AC Voltage

Experimental Study of the Flashover Process and the Leakage Current on the Surface of High Voltage Insulator Under AC Voltage

31W Linear broadband 3.4 to 4.4 GHZ high power class-j GaN HEMT amplifier

The recent upsurge in wireless communication systems requiring high-power transmitters for numerous applications such as electronic warfare (EW), RADAR, Satellite and optical communications has further underscored the importance of linear broadband high-power Class-J power amplifiers. This paper proposes a 31W linear broadband 3.4 to 4.4 GHz high-power Class-J GaN HEMT(gallium nitride high electron mobility transistor)amplifier. The power amplifier was designed based on Cree's commercially available 10WGaN HEMT power transistor device (CGHV40010F) using Keysight Advanced Design System (ADS) software and simulated. The transistor was biased withadrain supply voltage of 48V at aquiescent drain-to-source current of 0.58A,which makes the power transistor suitable for high voltage transmitter operations and foreclosed the need for voltage upgrade, thereby reducing thecost of operation. The power amplifier (PA) operates from 3.4 to 4.4 GHz with a centre frequency of 3.9 GHz. The PA has an output power of 31W, drain efficiency of 36.3%, power added efficiency of 35.3% and power gain of 12.9 dB at an input power of 32 dBm. The PA small signal gain stood at 10.6 dB at acentre frequency of 3.9 GHz. The PA maintained a peak envelope power of 56.2W at aninput power of 31 dBm at atwo-tone Frequency of 3.895 GHz. The proposed PA will find applications in wireless communications, military and aviation transmitters.

A SiC Photo-Conductive Switch-Based Pulse Generator with Nanoseconds and High Voltage for Liver Cancer Cells Ablation Therapy

Electroporation ablation, as an innovative cancer treatment, not only preserves the structure and function of affected organs but also significantly reduces surgical risks, offers patients a safer and more effective therapeutic option, and demonstrates immense potential in the field of oncology. This paper presents the innovative design of a high-voltage nanosecond pulse generator triggered by a silicon carbide (SiC) photoconductive switch. The generator is capable of stably outputting adjustable voltages ranging from 10 kV to 15 kV, with pulse widths precisely controlled between 10 and 15 nanoseconds, and an operating frequency adjustable from 1 Hz to 10 Hz. This device enables instant activation and deactivation of the pulse generator during ablation, enhancing the efficiency of strong electric field applications and preventing overtreatment due to delayed shutdown. This paper introduces the structure and basic principles of this novel SiC photoconductive switch-triggered pulse device and reports on the impact of device-related pulse parameters on the ablation effect of hepatocellular carcinoma cells through cell experiments. Under optimal ablation parameters, the CCK8 results show that the number of viable cells is only 0.7% of that in the untreated control group after 12 h of subculture following ablation. These findings hold significant importance for expanding the application areas of SiC devices.

Application of Digital Twin Technology in Substations: High Voltage Reactor Meter Visual Field Analysis of Phase A

This paper explores the application of Digital Twin (DT) technology in the monitoring and maintenance of high-voltage reactor meters within substations. Traditional inspection methods face limitations in covering the extensive areas and complex structures within substations, which DT technology can address by providing real-time monitoring, predictive analytics, and data-driven insights. The study focuses on visual field analysis for optimizing camera placement and configuration around high-voltage reactors, enhancing inspection accuracy and operational efficiency. Key components include IoT sensors, real-time analytics, and advanced visualization techniques. The findings suggest that DT-enabled systems significantly improve the reliability, safety, and efficiency of substation management, demonstrating potential for broader smart grid applications.

Assessment of transmission network connection solutions based on HVAC for offshore wind

AbstractThe diffusion of offshore wind power plants (OWPPs), useful to fulfil renewable diffusion policy targets, implies several technological challenges for integration in power transmission network. The definition of the OWPP connection to the transmission network affects possible exploitation of the assets, involves an evaluation of active power losses and loadability and points out the need for compensation devices, in order to comply with connection rules fixed by the grid operator. This paper proposes a methodology to determine the most suitable electric connection for an OWPP based on high‐voltage alternating current (HVAC) cables, for providing indications for transmission system operators. In particular, different HVAC connection schemes for OWPPs are analysed, focusing on new 66 kV standard voltage and high‐voltage levels, providing technical insight on transmission cable optimal operation conditions. An economic analysis is carried out by proper estimation of construction costs and production forecast, accounting for active power losses and reliability impact. The most suitable connection solution depending on OWPP size and distance in Italian framework is evaluated by means of synthetic techno‐economic indicators, further analysing possible sensitivities of energy price and capacity factor.

Ionic Exchange Mechanism in Electrical Double Layer Induced by Stable Passivation Film Boosts High Voltage Performance in Supercapacitors

Ionic Exchange Mechanism in Electrical Double Layer Induced by Stable Passivation Film Boosts High Voltage Performance in Supercapacitors

High gain multi-stage DC-DC boost converter using improved switched-inductor network with reduced voltage stress

ABSTRACT This article proposes a high-gain DC-DC boost converter employing an improved switched inductor (ISI) network coupled with CLD (capacitor-inductor-diode) cell (ISI-CLD-BC). The ISI network is further extended to an n-stage configuration, providing a multistage structure that enhances the attractiveness of the proposed converter for achieving high voltage gain. By Integrating a CLD cell at the load side, voltage stress across the active switch is reduced, enabling utilisation of lower-rated MOSFETs with reduced on-state resistance, thereby enhancing cost-effectiveness as well as efficiency. Furthermore, the CLD cell has the advantage of increasing the output voltage. The proposed converter’s steady-state performance in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is fully studied. Furthermore, the efficiency is analysed by evaluating different power losses of different elements. A small-signal model is derived for the proposed converter to evaluate the non-minimal phase condition followed by a PI controller design under closed-loop conditions. An exhaustive comparative study is conducted between the proposed converter and recently developed high-gain converters by considering various performance indices. Finally, the proposed converter is simulated in MATLAB/Simulink software and an experimental setup is created and tested to ensure its validity and efficacy.

Synergistic Enhancement of Cathode Performance through the Introduction of Oxygen Vacancies in the P2/P3 Mixed Phase.

P2-type NaxNiyMn1-yO2 cathodes have attracted attention due to their excellent stability and low cost, making them promising for sodium-ion batteries. However, their practical application is limited by a low capacity at lower voltages and severe phase transitions at higher voltage. To address these challenges, we report a material Na0.6Ni0.3Mn0.7O2-OVs (NNMO-OVs) with significantly slowed phase transitions at high voltage by introducing oxygen vacancies OVs into the P2/P3 mixed phase cathode Na0.6Ni0.3Mn0.7O2 (NNMO). Such a modification effectively broadens the Na+ diffusion pathways and enhances anionic redox reactions (ARR). As a result, an improved capacity of 173 mAh·g-1 at 1C is obtained by the desirable cathode within a voltage range of 1.5-4.3 V. Even at 10C, it exhibits a capacity of 60.1 mAh·g-1 between 2 and 4.1 V, maintaining 70.1% capacity retention after 700 cycles, showcasing impressive rate performance and cycling stability. Additionally, the P2/P3 mixed phase exhibits the presence of an OP4 intermediate phase during charging to high voltages, while the introduction of oxygen vacancies (OVs) further suppresses the P-O phase transition, maintaining only the P2-OP4 phase transition process.

Co-free gradient lithium-rich cathode for high-energy batteries with optimized cyclability

Lithium-rich layered oxides (LLOs) hold the promise for high-energy battery cathodes. However, its application has been hindered by voltage decay associated with irreversible reactions at high voltages despite decades of intensive efforts. Here, we first theoretically studied the molecular orbitals of Mn-based Li-rich configurations. We found that the π-bond ring formed within the LiMn6 structure could participate in stable redox reactions as one unit, but Co could disrupt its symmetry. We thus designed and synthesized Co-free concentration-gradient LLOs (CF-CG-LLOs) materials. The combination of concentration gradient and Co removal leads to exceptional capacity retention without any fading over 100 cycles of the pouch cell. More importantly, it exhibits an extraordinarily low voltage decay of 0.15 mV/cycle, accompanied by a high Coulombic efficiency of 99.86%. This concept and demonstration of CF-CG-LLO cathodes reveal a viable avenue toward low-cost, high-energy-density battery cathodes.

Mechanism of Multi-Physical Fields Coupling in Macro-Area Processing via Laser–Electrochemical Hybrid Machining (LECM)

Laser–electrochemical hybrid machining (LECM) is promising in the processing of thin-wall parts, which avoids problems such as the weak stiffness of structures and thermal defects. However, while most studies focus on precision machining via LECM, few investigate the potential of this technique in macro-area processing. In this paper, the synergistic effects on the coupling of thermal field and electrochemical field on bulk material removal mechanisms in the LECM of additively manufactured Ti6Al4V are comprehensively analyzed experimentally and theoretically. According to the experimental results, LECM improved the material removal rate (MRR) by up to 28.6% compared to ECM. The induction of the laser increases local heating, accelerating the temperature rise of the electrolyte, eventually promoting the electrochemical reaction. The hydrogen bubble flow promotes overall heat convection between the electrode and workpiece, which facilitates the removal of the facial precipitates and increases the efficiency of electrochemical dissolution. Higher voltages and laser powers promote the formation of hydrogen bubble flow; meanwhile, they also aggravate laser energy scattering, limiting the overall machining efficiency. Additionally, laser irradiation causes the ablation and rupture of hydrogen bubbles, which weakens the bubble flow effect and ultimately decreases the material removal efficiency. This study reveals the underlying mechanisms of the joint effects of the laser field and electrical field in LECM, and the findings can provide valuable insights for the optimization of LECM parameters in industrial applications.