Ternary transition metal oxides (TMOs) are deemed as promising anode materials of Li-ion batteries (LIBs) owing to their large theoretical capacity and rich redox reaction. Nevertheless, the inherent semiconductor characteristic and enormous volume variation of TMOs during cycling bring about sluggish reaction kinetics, fast capacity fading, and poor rate capability. In this study, three-dimensional (3D) porous CoNiO2@CTP architectures, i.e., CoNiO2 microspheres combined with coal tar pitch-derived porous carbon, were designed and synthesized through a one-step hydrothermal method followed by a heat treatment process for the first time. The microsphere morphology increases the contact area between the anode and electrolyte, shortens the transport distance of Li+ ions, and reduces the agglomeration. The existence of the CTP layer provides rich charge transmission paths, improves the electronic conductivity of CoNiO2 and provides abundant active sites for Li+ storage. Owing to the synergistic effect of porous carbon and microsphere morphology of CoNiO2, the CoNiO2@CTP (10.0 wt%) anode shows remarkable electrochemical performance with a high charge capacity (1437.5 mA h g-1 at 500 mA g-1), good rate performance (839.76 mA h g-1 even at 1 A g-1), and remarkable cycle durability (741.4 mA h g-1 after 1000 cycles at 1 A g-1), which is significantly better than pristine CoNiO2. This study not only provides a simple strategy for high-value utilization of CTP but also offers cost-effective CoNiO2@CTP architectures for high-performance LIBs.

Approaching high-performance lithium storage materials of CoNiO2 microspheres wrapped coal tar pitch-derived porous carbon.

Transition-metal sulfides are an intriguing family of electrocatalysts, yet their water-splitting applications are severely hampered by uncontrollable phase reconstruction and unsatisfactory in-service durability. Herein, we developed an efficient method to construct nickel sulfide (NiS) nanoarrays on foam nickel (NF) while being protected by highly N-doped formamide-derived carbon (termed NiS-NC@NF). The NiS nanocrystals were transformed in situ from highly dispersed Ni-N-C deposited on NF, ensuring a strong coupling effect that tunes the surface properties of NiS nanocrystals via the in situ constructed NiS/N-doped carbon interface. Electrochemical measurements reveal that very low overpotentials of 88.0 and 170.0 mV (vs. RHE) are required to achieve a current density of 10.0 mA cm-2 for hydrogen and oxygen evolution, respectively. The highly N-doped carbon matrix additionally regulates the potential-driven reconstruction of NiS in a controlled extent. Remarkably, the water electrolyzer built with NiS-NC@NF as both anode and cathode delivers an extremely low cell voltage of 1.51 V to initiate water splitting in the alkaline medium.

Constructing S-deficient nickel sulfide/N-doped carbon interface for improved water splitting activity

Empowering the fast-charging capability of Li-ion batteries is of common interest in the fields of portable electronic devices and electric vehicles, yet it currently faces challenges from unsatisfactorily high cycling stability at high rates. Herein, a thin layer of atomic Mo/N-codoped carbon is grown on commercial graphite (Gr) and used to regulate the formation of the solid electrolyte interface (SEI) and accelerate charge transfer at the Gr interface. The atomic Mo/N species (in the form of Mo1–NC) enable graphite with significantly reduced charge transfer and contact resistances and improved Li+ diffusion behavior through SEI and at the Gr interface. Electrochemical measurements show that compared to pristine Gr and Mo2C nanoparticle-modified Gr, Mo1–NC@Gr achieves much higher capacity and rate performance, rendering specific capacities of 443.7 and 159.9 mAh g–1 at 1.0 and 10.0 A g–1, respectively, while maintaining more than 90% capacity at a high rate of 3.0 A g–1 after 2000 cycles. 

Accelerating High-Rate Li-Ion Storage in Graphite via a Thin-Layer Coating of Atomic Mo–NC

Adjusting the micro-environment of highly dispersive metals on carbon supports has been proved to be effective for acquiring enhanced electrocatalysis performance. Herein, we delicately designed a phosphorus-doped binary NiFe-nitrogen-carbon material...

P-doped binary Ni/Fe-N-C for enhanced oxygen electrocatalysis performance

Open-end winding motor (OEWM) with dual inverter drive is adopted due to its excellent performance such as high DC voltage utilization, good fault tolerance, and large degrees of control freedom. This article presents a novel OEWM topology. Compared with the traditional OEWM, the novel topology proposed in this article provides higher fault tolerance by sharing bridge legs. It can achieve fault-tolerant operation under up to three bridge leg faults. Simulation results verify the effectiveness of proposed method.

Enhancing Fault Tolerant Ability of Motor Drive System Using Novel Open-end Topology

Although heteroatom doping and pore management separately influence the Li+ adsorption and Li+ diffusion properties, respectively, merging their functions into a single unit is intriguing and has not been fully investigated. Herein, we have successfully incorporated both heteroatom doping and pore management within the same functional unit of N4-vacancy motifs, which is realized via acid etching of formamide-derived Zn-N4-functionalized carbon materials (Zn1NC). The N4-vacancy-rich porous carbon (V-NC) renders multiple merits: (1) a high N content of 13.94 atom % for large Li-storage capacity, (2) edged unsaturated N sites favoring highly efficient Li+ adsorption and desolvation, and (3) a shortening of the Li+ diffusion length through N4 vacancy, thereby enhancing the Li-storage kinetics and high-rate performance. This work serves as an inspiration for the creation of heteroatom-edged porous structures with controllable pore sizes for high-rate alkali-ion battery applications.

N4-Vacancy-Functionalized Carbon for High-Rate Li-Ion Storage.

Compared with the traditional permanent magnet motor, the non-sinusoidal back-EMF permanent magnet motor can improve the torque density but when the motor fails, the back-EMF harmonics will produce torque ripple during the fault tolerance process. In this paper, the mathematical model of non-sinusoidal back-EMF motor is given and the torque ripple before and after fault is deduced. Based on the three-phase four-leg topology, a fault-tolerant control strategy for the open-phase fault of permanent magnet synchronous motor (PMSM) with the introduction of the third and fifth harmonic back-EMF is proposed in order to weaken the torque ripple caused by the introduced back-EMF harmonics. Finally, the effectiveness of the proposed control strategy is verified by simulation.

Fault-Tolerant Control of Three-Phase Four-Leg PMSM Servo Systems

Molybdenum oxide (MoO3) is an attractive anode material for lithium-ion batteries (LIBs); however, its low electrical conductivity, large volume expansion after lithiation, and slow Li-ion diffusion kinetics severely limit its practical applications. Here, ultrafine MoO3 nanoparticles (NPs) (10–15 nm) are synthesized from heavily Mo/N-doped carbonaceous precursors, resulting in MoO3 NPs confined in an N-doped carbon network. This design allows fast electron conduction and short Li-ion diffusion paths; meanwhile, abundant N species and O vacancies on the MoO3 surface lower the Li-ion adsorption barrier and together contribute to the durable Li-ion storage at high current rates. Notably, the obtained nanocomposite NC-MoO3 exhibits a high capacity of 1362 mA h g−1 (0.1 A g−1) and maintains a reversible capacity of 394 mA h g−1 at 10.0 A g−1. A coin-type full LiFePO4//NC-MoO3-400 cell obtains a large specific capacity of 81 mA h g−1 at 5 C. Our work inspires the design and confinement synthesis of other transition metal oxides embedded in conducting carbon networks for practical LIB applications. 

/pdf/qiang-ou-he-yang-hua-mu-dan-tan-fu-he-cai-liao-de-zhi-bei-ji-2fz1bn39.pdf

强耦合氧化钼氮碳复合材料的制备及其锂离子存储性能研究

The optimization process of traditional permanent magnet synchronous motor (PMSM) based on finite element calculation and control variable method has problems such as time-consuming and difficulty in achieving optimal design. It affects the solution efficiency and target response expectation of the PMSM multi-objective optimization problem. In order to solve the problem of high coupling degree of PMSM design factors and difficulty in visualizing the graph, the response surface nonlinear models with torque ripple and average torque per unit current as optimization objectives are established respectively in this paper based on factor significance analysis and central composite sequential experimental design method to realize the nonlinear mathematics modeling of PMSM under multi-variable interactive response. Subsequently, an improved response surface modeling method based on experimental space optimization is proposed to solve the problem of prediction deviation in response surface nonlinear modeling. This method constitutes a second-order response surface test scheme by adding appropriate test data points on the basis of the factorial experiment design, which can effectively improve the nonlinear modeling efficiency of the PMSM response surface.

Research on Response Surface Modeling Method of Permanent Magnet Synchronous Motor Based on Sequential Experimental Design

The break-in operation of the brake unit of a differential redundant actuation system is of considerable importance to improve its reliability and safety. However, the operation will generate a large impact on the driven load, which may cause damage to the load, and hence, it needs to be analyzed in detail. In this study, we first analyzed in detail the different working modes of a differential redundant actuation system and their dynamic characteristics during the break-in process. Subsequently, a dedicated offline test platform for the load simulation of the actuation system was designed to simulate rudders, i.e., the main type of load for such an actuation system. The test platform was used to perform experimental testing on the impact characteristics of the break-in process on the load under different working modes of the actuation system, and the relevant test data were obtained and evaluated accordingly. The experimental results show that, when the differential redundant actuation system is in a multiple-degrees-of-freedom state with a single input and multiple outputs, the break-in process of the brake unit has the smallest impact on the load; furthermore, when the backup channel of the differential redundant actuation system is in a locked state, the break-in process of the brake unit has the largest impact on the load.

Experimental Study on the Break-In Process of a Differential Redundant Actuation System Based on the Rudder Loop Load Simulation Platform

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