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We report the template-directed synthesis of sulphur-carbon nanotubes and their use to form a membrane that is binder-free, highly conductive and flexible. This nanostructured membrane is used as a self-supporting cathode without metal current-collectors for Li-S batteries. The membrane cathode has a high electrical conductivity and renders a long life of sulphur of over 100 charge-discharge cycles. High discharge capacity of sulphur was attained at 712 mA h g sulphur À1 (23 wt% S) and 520 mA h g sulphur À1 (50 wt% S) at a high current density (6 A g sulphur À1

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Vertically aligned carbon nanotubes (VACNTs) possess the advantages of a high degree of order, good controllability, and easy manipulation. Thus, their synthesis, properties, and potential for applications have been intensively investigated. [1][2][3][4][5] VACNTs are usually grown by chemical vapor deposition (CVD) on substrates with pre-deposited catalysts. Due to the rigorous CVD synthesis conditions, substrates employed for VACNT growth should be thermally and chemically stable materials, such as SiO 2 /Si, Al 2 O 3 , or quartz. A problem thus arising is that these substrates are usually insulators, which hampers the direct application of VACNTs in those areas that require desirable integrated electrical and thermal conductivities. [ 6 ] For example, a mismatching problem often emerges when assembling devices based on VACNTs due to the rigidity and poor conductivity of the substrates. To solve this problem, some researchers have developed multiform but complicated methods to transfer VACNTs from the insulating substrates to conducting substrates by post-synthesis processing, which facilitates the application of VACNTs in some electronic devices, such as fi eld emitters. [ 7,8 ] On the other hand, Tatsuki et al. reported direct growth of VACNTs on Ni-based alloy foils. [ 9 ] Although excellent fi eld emission homogeneity was demonstrated, the 30 nm thick alumina buffer layer deposited between the metal substrate and catalyst fi lm weakens the electrical contact and mechanical adhesion between the VACNTs and the metal substrate. The incompatible thermal expansion coeffi cients of alumina and metal may also lead to detaching of the VACNTs and the alumina buffer layer from the metal substrate.Graphene is a newly discovered 2D carbon material with excellent conductivity, mechanical properties, [ 10,11 ] and more importantly, compatibility with CNTs. Therefore, graphene can be an ideal substrate for VACNT growth. Recently, Lee et al. demonstrated the growth of VACNTs on a ∼ 7 nm thick reduced graphene fi lm supported by silicon wafer. The VACNT/ graphene hybrid fi lm infi ltrated with a poly(dimethyl siloxane) (PDMS) elastomer displayed good mechanical properties, electrical conductivity, and fi eld emission performance. [ 12 ] Nitrogendoped VACNTs grown on mechanically compliant graphene fi lm for a fl exible fi eld emitter were also demonstrated by Lee et al. [ 13 ] Jeong et al. reported a flexible room temperature NO 2 gas sensor consisting of a VACNT/reduced graphene hybrid film supported by a polyimide substrate. [ 14 ] Paul et al. prepared a 3D pillared graphene nanostructure comprising graphene and aligned carbon nanotubes by a one-step CVD method. [ 15 ] Zhang et al. demonstrated desirable visible light photocatalytic performance for a 3D pillared CNT/reduced graphene oxide composite material. [ 16 ] Fan et al. prepared a 3D CNT/graphene sandwich with short CNT pillars ( ∼ 100 nm in length) grown between graphene layers or by ultrasonicating purifi ed, shortcut CNTs in a graphene oxide suspension followed b...