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Constructing sodium‐ion battery anodes with efficient ion/electron transport and high cycling stability is significantly promising for applications but still remains challenging. Here, "three‐in‐one" multi‐level design is performed to develop a carbon‐coated phosphorous‐doped MoS2 anchored on carbon nanotube paper (P‐MoS2@C/CNTP). The Na+ diffusion and electron transport, as well as the structural stability of the whole anode are simultaneously enhanced through the synergistically optimization of P‐MoS2@C/CNTP at atomic, nanoscopic, and macroscopic levels. Resulted from the multi‐level modification, the synergetic mechanism has been demonstrated by electrochemical measurement and theoretical calculation. As a result, the free‐standing P‐MoS2@C/CNTP anode presents a high rate performance (150 mA h g−1 at 5 A g−1) and a long cycling life (1 A g−1, 1200 cycles, 249 mA h g−1). This work provides a new approach to the design and fabrication of high‐performance conversion‐type electrode materials for rechargeable batteries application. [ABSTRACT FROM AUTHOR]

Performance of a mechanical buffer can be significantly improved by strengthening the materials and optimizing its structure. Manufacturing of high-strength and light-weight foam-filled tubes (FFTs) has been proved to be an ingenious strategy. In this work, the in situ grown carbon nanotubes (CNTs) were used to reinforce aluminum (Al) foams. The FFTs were prepared by inserting CNT/Al composite foams (CFs) into 6061 Al alloy empty tubes (ETs). The crushing behavior and energy absorption property of the as-prepared CNT/Al FFTs (C-FFTs) were evaluated using uniaxial compressive tests. The results show that the adopted CFs can effectively interact with outside tubes in C-FFTs. The C-FFTs significantly improve the compressive performance and energy absorption property, but only slightly increase the structure weight compared to single ETs. The plateau stress and energy absorption capacity of C-FFTs are nearly 3.5 and 3.7 times higher than those of ETs, respectively. This phenomenon is ascribed to the stable support of CFs and the excellent load transfer ability of CNTs. [ABSTRACT FROM AUTHOR]

The compression‐compression fatigue performance of carbon nanotube (CNT) reinforced aluminium matrix composite foams (AMCFs) were investigated. The ε‐N curves of AMCFs are composed of three stages (the elastic, strain hardening, and rapid accumulation stages), while the fatigue strain of AMCFs accumulates very rapidly in stage III compared with Al foams. The fatigue strength of AMCFs with CNT contents of 2.0, 2.5, and 3.0 wt% increases by 6%, 44%, and 102% than Al foams, respectively. Different from Al foams' deformation of layer‐by‐layer, the main failure modes of AMCFs are the brittle fracture and collapse of pores within significant shear deformation bands under fatigue loading. The uniform distribution of CNTs and good interfacial bonding of CNTs and Al matrix is the important factor for the improvement of fatigue properties of AMCFs. [ABSTRACT FROM AUTHOR]

Metal oxide/carbon materials composites (MOx/C) are broadly used as electrodes in energy storage devices. However, their capacity under high rates is limited due to the sluggish ion/electron transportation during faradaic reactions. In this work, carbon nanotube carpets (CC)/Fe 2 O 3 nanoparticles covered with bud-liked carbon layer (CC/Fe 2 O 3 @b-C) is developed as an electrode by interfaces design. It is found that the bud-liked carbon wrapper enlarges interface area and provides an accelerated conducting network between CC and Fe 2 O 3 nanoparticles through "seamless" connection. With boosted charge transfer efficiency, this composite demonstrates an excellent rate capability. The CC/Fe 2 O 3 @b-C electrode shows a high capacity of 246.15 mC cm−2 under 5 mV s−1 and can maintain ~95% when the scan rate is increased to 100 mV s−1. Moreover, the hybrid device paired with carbon fiber cloth (CFC)/Co(OH) 2 cathode exhibits simultaneous high energy density and power density, showing good potential application in high-power devices. Image 1 • Bud-liked CNT carpets/Fe 2 O 3 @C were seamlessly connected through interfaces control. • Boosted charge transfer efficiency was obtained by perfectly matching R s and R ct. • Principles of designing MOx/C composites for energy storage devices were concluded. [ABSTRACT FROM AUTHOR]

• The carbon nanotubes (CNTs) reinforced closed-cell Al-Si composite foams (C-ASCFs) with CNTs content of 0.50 wt% have fatigue strength of 0.697 σ s (7.40 MPa), showing a superior improvement of the fatigue properties. • The appropriate incorporation of CNTs can change the fatigue failure mode, reduce the crack growth rate, and delay the fracture, hence raising the fatigue life. • The microstructure optimization of C-ASCFs influenced by CNT and its content was deeply investigated to interpret the influences on the fatigue properties of C-ASCFs. • The load transfer effect of CNTs in composite foams was firstly revealed, the contribution of which exhibits the largest of 2.07 MPa in 0.50 wt% C-ASCFs accounting for 22.5 % of its yield strength. As the requirement of compressive fatigue loading on the mechanical properties of aluminium foams increase rapidly, the limited fatigue performance of them significantly restricts their engineering applications. In this study, the compression-compression fatigue properties of carbon nanotubes (CNTs) reinforced closed-cell Al-Si composite foams (C-ASCFs) were investigated. The fatigue strength of C-ASCFs with 0.50 wt% CNTs increased by 54% than that of Al-Si foams, where the CNTs contributed to decrease the crack expansion rate, transfer the fatigue load and hence change the fatigue failure mode, causing a combination of plastic and brittle deformation in them. Meanwhile, the appropriate incorporation of CNTs decreased pore nucleation threshold, optimized the pore morphology, and promoted the formation and refinement of eutectic Si. Such inhibited the probability of fatigue cracks initiation, resulting in the enhancement of fatigue life. This work provides theoretical and practical basis of design strategy of Al-Si composite foams and broadens their application prospect. [ABSTRACT FROM AUTHOR]

The incorporation of nano carbon reinforcement is a useful strategy to broaden the engineering applications of metal foams. In this work, carbon nanotubes (CNTs) reinforced aluminum (Al) matrix composite foams (CNTs/Al composite foams) with different CNTs content are prepared by combining ball-milling technique with powder metallurgy method. The result shows that the appropriate content of CNTs can reduce the pore size, improve the circularity, and enhance the compressive properties. Especially, the 1.0 wt% CNTs/Al composite foams possess the optimal compressive properties of yield stress (7.90 MPa), plateau stress (8.75 MPa) and energy absorption capacity (5.19 MJ/m3), which have an enhancement of 23.24%, 98.41% and 84.70%, respectively. Composite foams undergo shear deformation throughout the quasi-static compression process, and the failure mode performs as the brittle mode combined with ductile mode. Meanwhile, the incorporation of CNTs can contribute to the inhomogeneous distribution of the Si phase, provide more nucleation sites, and significantly refine the pore size. It is confirmed that the CNTs in composite foams contribute the grain refinement and the formation of micro stacking faults, making the mechanical properties of CNTs/Al composite foams outperform the counterpart of Al-Si foams. Moreover, due to the weak interfacial reaction, the low content of aluminum carbide is formed, which can promote the load transfer between CNTs and Al. The present finding provides a theoretical and practical design strategy to the future preparation of CNTs/Al composite foams. • The CNTs/Al composite foams with CNTs content of 1.0 wt% show a superior improvement of the compressive properties. • The incorporation of CNTs can contribute to the inhomogeneous distribution of the Si phase and refine the grain size. • The deformation and failure mode of CNTs/Al composite foams are affected by the content of CNTs. • The formation of aluminum carbides and micro stacking faults benefit to promote the compressive properties of composite foams. [ABSTRACT FROM AUTHOR]

Highlights • A novel and efficient method to fabricate CNTs reinforced Al alloy matrix composite foams is put forward. • CNTs are homogeneously dispersed in the matrix. • The effects of CNTs on pore structure during foaming process is discussed. Abstract Uniformly dispersed carbon nanotubes (CNTs) reinforced aluminum (Al) alloy matrix composite foams were successfully fabricated by the combination of in-situ chemical vapor deposition and powder metallurgy using titanium hydride as a blowing agent. The effects of CNTs on the pore structure were systematically studied. The results showed that compared to the Al alloy foam, the introduction of CNTs could significantly improve the pore uniformity and reduce the pore size. As a result, the compressive property of composite foam had an obvious increase. The reasons for the enhanced pore structure mainly lie in that the CNTs increased nucleation sites for the decomposed hydrogen and the limited the movements of bubbles in the melt during foaming process. [ABSTRACT FROM AUTHOR]

Developing high-capacity anodes with fast kinetics and stable structure is critical for the effective implementation of sodium ion capacitors (SICs). In this study, Fe 2 O 3 @C nanoparticles modified vertically aligned carbon nanotubes (VACNTs) composites are designed and employed as SIC anodes through a two-step chemical vapor deposition (CVD) process with the aid of a refined Fe 3 O 4 /AlO x dispersion catalyst. With nano-sized Fe 2 O 3 coated with defected carbon layers sufficiently loading onto the VACNTs substrates, the resulting composites demonstrate remarkable sodium storage properties, with a high areal specific capacity (1.26 mAh cm−2 at 0.2 mA cm−2) and rate performance (0.19 mAh cm−2 at 5.0 mA cm−2). Moreover, continuous capacity promotion is observed over 1000 cycles, leading to superior cycling performance (0.444 mAh cm−2 at 1 mA cm−2), with 178% retention after 1000 cycles. This improved cycling performance is attributed to the defective structure and high specific surface area of the VACNTs, which accommodates the volume change of the Fe 2 O 3 particles. In addition, the induced locally graphitization and rearrangement of the carbon layers are demonstrated, which results in better kinetics for Na+ transfer, further enhancing capacity retention over long cycles. [Display omitted] • Fe 2 O 3 @C/VACNTs composites realized superior synergistic effect. • Sustained increasing for capacities were obtained by modifying nano-sized Fe 2 O 3 @C. • Refined Fe 2 O 3 paritcles and Na + insertion inducing graphtization was investigated. [ABSTRACT FROM AUTHOR]

Germanium is a promising anode for lithium ion batteries (LIB) because of its potential rate capability and high theoretical specific capacity. Here we demonstrate a seamlessly connected graphene and carbon nanotube (GCNT) hybrid that serves as an integral current collector for a Ge anode. A vertically aligned CNT (VA-CNT) forest grown on graphene provides a high surface area for Ge deposition. The seamless connection between graphene and VA-CNT facilitates electron transport from the Ge to the Cu current collector. Graphene serves to alleviate mechanical strain between the electrode and current collector. The mechanical resilience of the GCNT lessens Ge pulverization on charge/discharge of the LIB. As a result, the Ge/GCNT anode has a high specific capacity of 1315 mAh/g after 200 cycles at 0.5 A/g and a high rate performance of 803 mAh/g at 40 A/g. [ABSTRACT FROM AUTHOR]

This study presents the results of quasi-static compressive tests of aluminum (Al) foam-filled tubes (A-FFTs) and Carbon Nanotubes (CNTs)/Al composite foam-filled tubes (C-FFTs) prepared by in-situ filling space-holder method. The effects of processing parameters and interface interaction between foam fillers and tubes on mechanical properties and deformation behaviors of the C-FFTs are analyzed, through both the macro- and micro-scopic characterizations. The results show that both cold pressing and sintering can improve the interface connection between foam fillers and tubes. Besides, the addition of CNTs not only increases the strength of foam fillers, but also changes the deformation mode of foam fillers from layer-by-layer shear failure to overall shear failure, which in turn influences the mechanical properties of foam-filled tubes (FFTs). Meanwhile, the interface between foam fillers and tubes (macro interface) of the A-FFTs shows a metallurgical bonding because of the atom diffusion during cold pressing and sintering processes, and as a result, the energy absorption capability of the A-FFTs and 2.5 wt% C-FFTs are increased by 51.3% and 45.8%, respectively. Based on the current findings, a distinctive deformation behavior associated with the interaction effect is proposed. [ABSTRACT FROM AUTHOR]