Luzhuo Chen

An efficient bifunctional catalyst of Fe/Fe3C carbon nanofibers for rechargeable Li–O2 batteries

Designing an efficient catalyst is essential to improve the electrochemical performance for Li–O2 batteries. In this study, the novel composites of Fe/Fe3C carbon nanofibers (Fe/Fe3C–CNFs) were synthesized via a facile electrospinning method and used as cathode catalysts for Li–O2 batteries. Owing to their favorable structures and desirable bifunctional catalytic activities, the resulting cathodes with a Fe/Fe3C–CNF catalyst exhibited superior electrochemical performance with high specific capacity, good rate capability and cycle stability. It is revealed that the synergistic effect of the fast kinetics of electron transport provided by the CNF support and the high electro-catalytic activity provided by the Fe/Fe3C composites resulted in the excellent performance for Li–O2 batteries. The preliminary result manifests that the composites of Fe/Fe3C–CNFs are promising cathode electrocatalysts for Li–O2 batteries.

A large-deformation phase transition electrothermal actuator based on carbon nanotube–elastomer composites

An electrothermal phase transition actuator based on a superaligned carbon nanotube film and elastomers has been designed and fabricated. Compared with a conventional electrothermal bimorph actuator using cantilever structures, this new-type actuator introduces a novel concept of phase transition large-deformation actuation. The actuator consists of an enclosed cavity made up of highly elastic elastomers and an embedded carbon nanotube based electrical heater. A low-boiling liquid was injected into the cavity and it can vaporize rapidly to make the elastic cavity expand significantly when electrically heated. The size and speed of the expansion can be easily controlled by the applied voltage (electrical power). The expanded elastomer membrane can lift more than 1000 times of its own weight. The cyclic actuation test shows the excellent durability of the actuator. A heart-shaped closed liquid circulation system based on the phase transition pump-type actuators has been made, which can work like a real heart. Owing to the advantages of low driving voltage, large deformation, simple fabrication, easy operation, lightweight and durability, we think that the phase transition actuator will have great potential usage in various areas, such as artificial muscles, soft robots, sensors, and especially in the biomedical field.

Design and optimization of carbon nanotube/polymer actuator by using finite element analysis*

In recent years, actuators based on carbon nanotube (CNT) or graphene demonstrate great potential applications in the fields of artificial muscles, smart switches, robotics, and so on. The electrothermal and photothermal bending actuators based on CNT/graphene and polymer composites show large bending actuations, which are superior to traditional thermal-driven actuators. However, the influence of material parameters (thickness, temperature change, etc.) on the actuation performance needs to be further studied, because it is a critical point to the design and fabrication of high-performance actuators. In this work, finite element analysis (FEA) is employed to simulate the actuation performance of CNT/polymer actuator, which has a bilayer structure. The main focus of this work is to design and to optimize material parameters by using computational method. FEA simulation results show that each layer thickness of actuator has an important influence on the actuation deformation. A maximum curvature of 2.7 cm is obtained by simulation, which is much larger than most of the actuator curvature reported in previous experiments. What is more, larger temperature change and larger difference of coefficient of thermal expansion (CTE) between two layers will result in larger bending actuation. This study is expected to provide valuable theoretical reference for the design and realization of CNT-based thermal actuator with ultra-large actuation performance.

NiSnO3 nanoparticles/reduced graphene oxide composite with enhanced performance as a lithium-ion battery anode material

NiSnO3 nanoparticles (NPs) were loaded on reduced graphene oxide (RGO) by a facile hydrothermal technique as a anode material for lithium ion batteries (LIBs). It was found that the NiSnO3/RGO anode exhibits improved LIBs performance compared to bare NiSnO3 or RGO. The NiSnO3/RGO anode can maintain a reversible capacity of 792 mA h g−1, tested at 1200 mA g−1 after 60 cycles. When the current density was lowered in a test of rate capacity, the charge capacity was completely restored after high rate cycling at 6000 mA g−1 and maintained 889 mA h g−1 at 200 mA g−1 after 115 cycles. The enhanced LIBs performance of the NiSnO3/RGO nanocomposites can be attributed to the synergistic effects between a highly loaded NiSnO3 NPs and graphene network.