Li‐dendrite growth and unsatisfactory sulfur cathode performance are two core problems that restrict the practical applications of lithium–sulfur batteries (LSBs). Here, an all‐in‐one design concept for a Janus separator, enabled by the interfacial engineering strategy, is proposed to improve the performance of LSBs. At the interface of the anode/separator, the thin functionalized composite layer contains high‐elastic‐modulus and high‐thermal‐conductivity boron nitride nanosheets and oxygen‐group‐grafted cellulose nanofibers (BNNs@CNFs), by which the formation of “hot spots” can be effectively avoid, the Li‐ion flux homogenized, and dendrite growth suppressed. Meanwhile, at the interface between the separator and the cathode, the homogenously exposed single‐atom Ru on the surface of reduced graphene oxide (rGO@Ru SAs) can “trap” polysulfides and reduce the activation energy to boost their conversion kinetics. Consequently, the LSBs show a high capacity of 460 mAh g–1 at 5C and ultrastable cycling performance with an ultralow capacity decay rate of 0.046% per cycle over 800 cycles. To further demonstrate the practical prospect of the Janus separator, a lithium–sulfur pouch cell using the Janus separator delivers a cell‐level energy density of 310.2 Wh kg–1. This study provides a promising strategy to simultaneously tackle the challenges facing the Li anode and the sulfur cathode in LSBs.

In inverted perovskite solar cells (PSCs), the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is a widely used electron transport material. However, a high degree of energy disorder and inadequate passivation of PCBM limit the efficiency of devices, and severe self-aggregation and unstable morphology limit the lifespan of devices. Here, we design a series of fullerene dyads FP-Cn (n = 4, 8, 12) to replace PCBM as an electron transport layer, where [60]­fullerene is linked with a terpyridine chelating group via a flexible alkyl chain of different lengths as a spacer. Among three fullerene dyads, FP-C8 shows the most enhanced molecule ordering and adhesion with the perovskite surface due to the balanced decoupling between the chelation effect from terpyridine and the self-assembly of fullerene, leading to lower energy disorder and higher morphological stability relative to PCBM. The FP-C8/C60-based devices using Cs0.05FA0.90MA0.05PbI2.85Br0.15 as a light absorber show a power conversion efficiency of 21.69%, higher than that of PCBM/C60 (20.09%), benefiting from improved electron extraction and transport as well as reduced charge recombination loss. When employing FAPbI3 as a light absorber, the FP-C8/C60-based devices exhibit an efficiency of 23.08%, which is the champion value of inverted PSCs with solution-processed fullerene derivatives. Moreover, the FP-C8/C60-based devices show better moisture and thermal stability than PCBM/C60-based devices and maintain 96% of their original efficiency after 1200 h of operation, while their counterpart PCBM/C60 maintains 60% after 670 h.

Two-dimensional structures composed solely of pentagonal motifs are of particular interest due to their unique geometries and novel properties. Especially, the broken centrosymmetry in many pentagon-based sheets results in piezoelectricity....

Based on first-principles calculations, we propose a new 3D topological nodal-net carbon allotrope consisting of graphene nanoribbons. This structure possesses orthorhombic symmetry with 46 carbon atoms in its primitive cell,...

Quasi‐2D (Q‐2D) perovskites are promising candidates to apply in light‐emitting diodes (LEDs). However, delicate control on crystallization kinetics is needed to suppress severe phase segregation. Here, the crystallization kinetics of Q‐2D perovskites are investigated via in situ absorbance spectroscopy and for the first time find the multiphase distribution is governed by the arrangement, rather than diffusion, of spacer cations at the nucleation stage, which associate with its assembling ability determined by molecular configuration. A “co‐assembly” strategy is conceived by combining co‐cations with different configuration characteristics, where bulky cations disturb the assembling between slender cations and lead–bromide sheet, contributing to homogeneous emitting phase with effective passivation. Correspondingly, in the phenylethylammonium (PEA+)‐based Q‐2D perovskites (<n> = 3), homogeneous phase distribution is achieved by incorporating co‐cation triphenylmethaneammonium (TPMA+), the branching terminals of which suppress cations assembling into low‐n phases and afford adequate cations as passivating ligands. Therefore, the champion external quantum efficiency of the LED device reaches 23.9%, which is among the highest performance of green Q‐2D perovskite LEDs. This work reveals that the arrangement of spacer cations determines the crystallization kinetics in Q‐2D perovskites, providing further guidance on the molecular design and phase modulation of Q‐2D perovskites.