Herein, a hierarchically micro/mesoporous nanocomposite of graphene and carbon nanospheres (HGC) is used as an immobilizer for a lithium−sulfur (Li−S) battery with enhanced performance. HGC derived from graphene oxides and polyvinylidene fluoride polymers, combined with the advantages of graphene and porous carbon nanospheres, exhibits a hierarchically micro/ mesoporous structure with an ultralarge specific surface area of up to 3182 m 2 g −1 and a large pore volume of 1.91 cm 3 g −1 . Graphene as a conducting network can enhance electronic conductivity, while porous nanospheres like a reservoir can effectively store and immobilize sulfur particles. HGC/sulfur electrode material obtained via a melting infusion process exhibits high reversible specific capacity of 1250 mA h g −1 with a high sulfur content of 74.5 wt %, and it still has a capacity of 916 mA h g −1 after 100 cycles, which is better than that of pristine porous graphene and carbon nanospheres. Furthermore, the relative capacity decay of the HGC/sulfur electrode is only 0.005 and 0.004% per cycle at 2 C and 4 C, respectively, after 450 charge/discharge cycles, exhibiting remarkable performance in terms of long-term electrochemical stability.

In one-dimensional (1D) systems, electronic interactions lead to a breakdown of Fermi liquid theory and the formation of a Tomonaga-Luttinger Liquid (TLL). The strength of its many-body correlations can be quantified by a single dimensionless parameter, the Luttinger parameter K, characterising the competition between the electrons’ kinetic and electrostatic energies. Recently, signatures of a TLL have been reported for the topological edge states of quantum spin Hall (QSH) insulators, strictly 1D electronic structures with linear (Dirac) dispersion and spin-momentum locking. Here we show that the many-body interactions in such helical Luttinger Liquid can be effectively controlled by the edge state’s dielectric environment. This is reflected in a tunability of the Luttinger parameter K, distinct on different edges of the crystal, and extracted to high accuracy from the statistics of tunnelling spectra at tens of tunnelling points. The interplay of topology and many-body correlations in 1D helical systems has been suggested as a potential avenue towards realising non-Abelian parafermions.

The interplay of topology and superconductivity has become a subject of intense research in condensed matter physics for the pursuit of topologically non-trivial forms of superconducting pairing. An intrinsically normal-conducting material can inherit superconductivity via electrical contact to a parent superconductor via the proximity effect, usually understood as Andreev reflection at the interface between the distinct electronic structures of two separate conductors. However, at high interface transparency, strong coupling inevitably leads to changes in the band structure, locally, owing to hybridization of electronic states. Here, we investigate such strongly proximity-coupled heterostructures of monolayer 1T'-WTe2, grown on NbSe2 by van-der-Waals epitaxy. The superconducting local density of states (LDOS), resolved in scanning tunneling spectroscopy down to 500 mK, reflects a hybrid electronic structure, well-described by a multi-band framework based on the McMillan equations which captures the multi-band superconductivity inherent to the NbSe2 substrate and that induced by proximity in WTe2, self-consistently. Our material-specific tight-binding model captures the hybridized heterostructure quantitatively, and confirms that strong inter-layer hopping gives rise to a semi-metallic density of states in the 2D WTe2 bulk, even for nominally band-insulating crystals. The model further accurately predicts the measured order parameter ∆ 0.6 meV induced in the WTe2 monolayer bulk, stable beyond a 2 T magnetic field. We believe that our detailed multi-band analysis of the hybrid electronic structure provides a useful tool for sensitive spatial mapping of induced order parameters in proximitized atomically thin topological materials.