Property by design is one appealing idea in material synthesis but hard to achieve in practice. A recent successful example is the demonstration of van der Waals (vdW) heterostructures, 1-3 in which atomic layers are stacked on each other and different ingredients can be combined beyond symmetry and lattice matching. This concept, usually described as a nanoscale Lego blocks, allows to build sophisticated structures layer by layer. However, this concept has been so far limited in two dimensional (2D) materials. Here we show a class of new material where different layers are coaxially (instead of planarly) stacked. As the structure is in one dimensional (1D) form, we name it "1D vdW heterostructures". We demonstrate a 5 nm diameter nanotube consisting of three different materials: an inner conductive carbon nanotube (CNT), a middle insulating hexagonal boron nitride nanotube

A large-area flexible polymer electrode is fabricated using a new type of polyimide/single-walled carbon nanotube (SWCNT) nanocable composite. SWCNTs serve as the current collector and conductive network, and polyimide nanoparticles anchored on carbon nanotubes act as active materials. The electrode shows superior rate performance, good cycling stability, and high flexibility.

A novel polyimide derivative PMAQ is prepared by a condensation polymerization of pyromellitic dianhydride and 2, 6diaminoanthraquinone and a flexible electrode film PMAQ-SWNT is further fabricated by filtration with single-wall carbon nanotube dispertions. PMAQ connets different carbonyl groups of dianhydride and quinone together, therefore combines the advantages of different units together. Electrochemical tests show that PMAQ-SWNT can transfer three electrons reversibly and theoretical calculation also prove that. PMAQ-SWNT shows high capacity of 190 mA h g −1 and superior rate performance, remaining 120 mA h g −1 at 20 C. PMAQ-SWNT is a promising flexible electrode because of good performance and flexibility.

Synthesis of single-walled carbon nanotubes (SWNTs) with well-defined atomic arrangements has been widely recognized in the past few decades as the biggest challenge in the SWNT community, and has become a bottleneck for the application of SWNTs in nano-electronics. Here, we report a selective synthesis of (12, 6) SWNTs with an enrichment of 50%-70% by chemical vapor deposition (CVD) using sputtered Co-W as a catalyst. This is achieved under much milder reduction and growth conditions than those in the previous report using transition-metal molecule clusters as catalyst precursors (Nature, 2014, 510, 522). Meanwhile, in-plane transmission electron microscopy unambiguously identified an intermediate structure of Co6W6C, which is strongly associated with selective growth. However, most of the W atoms disappear after a 5 min CVD growth, which implies that anchoring W may be important in this puzzling Co-W system.