Designing flexible free-standing air-electrode with efficient OER/ORR performance is of vital importance for the application of Zinc-air batteries in flexible electronics.Herein,a flexible free-standing electrode(Ni/F...Designing flexible free-standing air-electrode with efficient OER/ORR performance is of vital importance for the application of Zinc-air batteries in flexible electronics.Herein,a flexible free-standing electrode(Ni/Fe-NC/NCF/CC)is synthesized by in-situ coupling of binary Ni/Fe-NC nanocubes and N-doped carbon nanofibers(NCF)rooted on carbon cloth.The highly dispersed binary Ni/Fe-NC sites ensure excellent ORR activity and create efficient OER active sites relative to Ni-NC and Fe-NC.The in-situ coupling of Ni/Fe-NC and NCF constructs a 3D interconnected network structure that not only provides abundant and stabilized reactive sites but also guarantees fast electron transfer and gas transportation,thus achieving efficient and fast operation of ORR/OER.Therefore,Ni/Fe-NC/NCF/CC displays a much positive potential(0.952 V)at 4.0 mA cm^(-2)for ORR and a low OER overpotential(310 mV)at 50 mA cm^(-2).The Zinc-air battery with Ni/Fe-NC/NCF/CC air-electrode exhibits excellent battery performance with outstanding discharge/charge durability for 2150 cycles.The flexible Zn-air batteries with foldable mechanical properties display a high power density of 105.0 mW cm^(-2).This work widened the way to prepare flexible bifunctional air-electrode by designing composition/structure and in-situ coupling.展开更多
Integrating high content carbon into the negative electrodes of advanced lead–acid batteries effectively eliminates the sulfation and improves the cycle life,but brings the problem of hydrogen evolution,which increas...Integrating high content carbon into the negative electrodes of advanced lead–acid batteries effectively eliminates the sulfation and improves the cycle life,but brings the problem of hydrogen evolution,which increases inner pressure and accelerates the water loss.In this review,the mechanism of hydrogen evolution reaction in advanced lead–acid batteries,including lead–carbon battery and ultrabattery,is briefly reviewed.The strategies on suppression hydrogen evolution via structure modifications of carbon materials and adding hydrogen evolution inhibitors are summarized as well.The review points out effective ways to inhibit hydrogen evolution and prolong the cycling life of advanced lead–acid battery,especially in high-rate partial-state-of-charge applications.展开更多
We present in this paper a robust online path planning method, which allows a micro rotorcraff drone to fly safely in GPS-denied and obstacle-strewn environments with limited onboard computational power. The approach ...We present in this paper a robust online path planning method, which allows a micro rotorcraff drone to fly safely in GPS-denied and obstacle-strewn environments with limited onboard computational power. The approach is based on an effi- ciently managed grid map and a closed-form solution to the two point boundary value problem （TPBVP）. The grid map assists trajectory evaluation whereas the solution to the TPBVP generates smooth trajectories. Finally, a top-level trajectory switching algorithm is utilized to minimize the computational cost. Advantages of the proposed approach include its conservation of com- putational resource, robustness of trajectory generation and agility of reaction to unknown environment. The result has been realized on actual drones platforms and successfully demonstrated in real flight tests. The video of flight tests can be found at： http：//uav.ece.nus.edu.sg/robust-online-path-planning-Lai2015.html.展开更多
基金supported by the National Natural Science Foundation of China(Grants:51861135315,U1766216,51774148,51804128,52177215,51977097)
文摘Designing flexible free-standing air-electrode with efficient OER/ORR performance is of vital importance for the application of Zinc-air batteries in flexible electronics.Herein,a flexible free-standing electrode(Ni/Fe-NC/NCF/CC)is synthesized by in-situ coupling of binary Ni/Fe-NC nanocubes and N-doped carbon nanofibers(NCF)rooted on carbon cloth.The highly dispersed binary Ni/Fe-NC sites ensure excellent ORR activity and create efficient OER active sites relative to Ni-NC and Fe-NC.The in-situ coupling of Ni/Fe-NC and NCF constructs a 3D interconnected network structure that not only provides abundant and stabilized reactive sites but also guarantees fast electron transfer and gas transportation,thus achieving efficient and fast operation of ORR/OER.Therefore,Ni/Fe-NC/NCF/CC displays a much positive potential(0.952 V)at 4.0 mA cm^(-2)for ORR and a low OER overpotential(310 mV)at 50 mA cm^(-2).The Zinc-air battery with Ni/Fe-NC/NCF/CC air-electrode exhibits excellent battery performance with outstanding discharge/charge durability for 2150 cycles.The flexible Zn-air batteries with foldable mechanical properties display a high power density of 105.0 mW cm^(-2).This work widened the way to prepare flexible bifunctional air-electrode by designing composition/structure and in-situ coupling.
基金supported by the Science and Technology Program of State Grid Corporation of Chinathe National Thousand Talents Program of China
文摘Integrating high content carbon into the negative electrodes of advanced lead–acid batteries effectively eliminates the sulfation and improves the cycle life,but brings the problem of hydrogen evolution,which increases inner pressure and accelerates the water loss.In this review,the mechanism of hydrogen evolution reaction in advanced lead–acid batteries,including lead–carbon battery and ultrabattery,is briefly reviewed.The strategies on suppression hydrogen evolution via structure modifications of carbon materials and adding hydrogen evolution inhibitors are summarized as well.The review points out effective ways to inhibit hydrogen evolution and prolong the cycling life of advanced lead–acid battery,especially in high-rate partial-state-of-charge applications.
文摘We present in this paper a robust online path planning method, which allows a micro rotorcraff drone to fly safely in GPS-denied and obstacle-strewn environments with limited onboard computational power. The approach is based on an effi- ciently managed grid map and a closed-form solution to the two point boundary value problem （TPBVP）. The grid map assists trajectory evaluation whereas the solution to the TPBVP generates smooth trajectories. Finally, a top-level trajectory switching algorithm is utilized to minimize the computational cost. Advantages of the proposed approach include its conservation of com- putational resource, robustness of trajectory generation and agility of reaction to unknown environment. The result has been realized on actual drones platforms and successfully demonstrated in real flight tests. The video of flight tests can be found at： http：//uav.ece.nus.edu.sg/robust-online-path-planning-Lai2015.html.
