Efficient piezo-catalytic dye degradation using piezoelectric 6H-SiC under harsh conditions

The development of novel piezoelectric catalysts against harsh conditions is indeed crucial for improving the piezo-catalytic degradation efficiency of colored organic dyes in wastewater.In this work,6H-SiC nanoparticles(NPs)are utilized to piezo-catalytic degrade rhodamine B(RhB)and methylene blue(MB)under ultrasonic vibration for the first time.The degradation efficiency of RhB and MB reaches 98.8%and 98.7%within 80 min.The piezoelectricity of 6H-SiC is comprehensively analyzed by the piezoresponse force microscope(PFM)and finite element method(FEM).The strong oxidizing active free radicals generated by the continuous piezoelectric polarized electric field of 6H-SiC,i.e.,·O_(2)^(-)and·OH,induce the decomposition reactions of colored organic dyes in solution.And the dyes are proven to degrade to harmless or less-harmful products gradually during the piezo-catalysis process by high-performance liquid chromatography tandem mass spectrometry(HPLC-MS).Moreover,RhB is also decomposed efficiently by 6HSiC NPs under acidic and alkaline conditions.These results prove the feasibility of 6H-SiC for decomposing common water pollutants under harsh conditions and provide a new perspective for water purification.

Boosting lithium batteries under harsh operating conditions by a resilient ionogel with liquid-like ionic conductivity

New chemistries are being developed to increase the capacity and power of rechargeable batteries. However, the risk of safety issues increases when high-energy batteries using highly active materials encounter harsh operating conditions. Here we report on the synthesis of a unique ionogel electrolyte for abuse-tolerant lithium batteries. A hierarchically architected silica/polymer scaffold is designed and fabricated through a facile soft chemistry route, which is competent to confine ionic liquids with superior uptake ability (92.4 wt%). The monolithic ionogel exhibits high conductivity and thermal/mechanical stability, featuring high-temperature elastic modulus and dendrite-free lithium cycling. The Li/LiFePO_(4) pouch cells achieve outstanding cyclability at different temperatures up to 150 ℃, and can sustain cutting, crumpling, and even coupled thermal–mechanical abuses. Moreover, the solid-state lithium batteries with LiNi_(0.60)Co_(0.20)Mn_(0.20)O_(2), LiNi_(0.80)Co_(0.15)Al_(0.05)O_(2), and Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) cathodes demonstrate excellent cycle performances at 60 ℃. These results indicate that the resilient and high-conductivity ionogel electrolyte is promising to realize high-performance lithium batteries with high energy density and safety.

Cascade Optimization Control of Unmanned Vehicle Path Tracking Under Harsh Driving Conditions

Under ultra-high-speed and harsh conditions,conventional control methods struggle to ensure the path tracking accuracy and driving stability of unmanned vehicles during the turning process.Therefore,this study proposes a cascade control to solve this problem.Based on the new vehicle error model that considers vehicle tire sideslip and road curvature,the feedforward-parametric adaptive linear quadratic regulator(LQR)and proportional integral control-based speed-keeping controllers are used to compose the path-tracking cascade optimization controller for unmanned vehicles.To improve the adaptability of the unmanned vehicle path-tracking control under harsh driving conditions,the LQR controller parameters are automatically adjusted using a back-propagation neural network,in which the initial weights and thresholds are optimized using the improved grey wolf optimization algorithm according to the driving conditions.The speed-keeping controller reduces the impact on the curve-tracking accuracy under nonlinear vehicle speed variations.Finally,a joint model of MATLAB/Simulink and CarSim was established,and simulations show that the proposed control method can achieve stable entry and exit curves at ultra-high speeds for unmanned vehicles.Under strong wind and ice road conditions,the method exhibits a higher tracking accuracy and is more adaptive and robust to external interference in driving and variable curvature roads than methods such as the feedforward-LQR,preview and pure pursuit controls.

Post lithium-sulfur battery era:challenges and opportunities towards practical application

Lithium-sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system owing to the high theoretical energy density and natural abundance of sulfur.Abundant fundamental researches have pushed the flourishing development on electrochemical behaviors in recent 20 years.It is time to evolve into post-Li-S battery era with the pursuit towards practical application.During the landmark leap,numerous new challenges appear under harsh conditions,such as high sulfur loading,low cathode density,lean electrolyte and limited lithium reservoir.Herein,we summarize the considerable parameters of pouch Li-S cells and review the pioneering studies focused on the cathode structure,conversion kinetics,electrode interphase and battery safety.The interwoven relationship of these key points is concluded and discussed,which provides guidance to future researches aiming to safe and long-lifespan Li-S batteries with high energy density.