separators used in LIBs are made of polyolefin such as polypropylene (PP), which typically suffers from low porosity, inferior electrolyte wettability, and poor thermal stability. [8,9] Moreover, the wide pore size distribution of PP separators leads to inhomogeneous Li-ion flux during charging and discharging, which can potentially induce the growth of Li dendrites puncturing the separator, thereby causing the dreadful safety hazard. [10,11] In the past decade, many efforts have been concentrated on designing new separators beyond polyolefin or modifying polyolefin-based separators. [12][13][14][15][16] For instance, non-polyolefin (e.g., polyacrylonitrile) separators with increased porosity and enhanced electrolyte wettability have been fabricated by the electrospinning method, [17] but their poor mechanical strength and thermal stability make them less attractive in commercialization. On the other hand, inorganic nanoparticles such as Al 2 O 3 have been introduced to modify the surface of polyolefin membranes to achieve enhanced electrolyte wettability and thermal stability. [18][19][20] These modification methods, however, inevitably increase the thickness of separators and sacrifice the energy density of LIBs. [21] Nevertheless, there still remains a challenge to develop ultralight separators with allround performance (i.e., high porosity, excellent electrolyte wettability, and sufficient thermal stability and mechanical strength).Silica (SiO 2 ) particles have been widely used in medicine, photonics, and catalysis, owing to their environmental friendliness, low cost, and ease of production. [22][23][24][25][26] Recently, SiO 2 particles have been exploited to modify the surface of polymer (e.g., PP) separators to improve the thermal stability and electrolyte affinity. [27] Moreover, SiO 2 particles have also been used as fillers to enhance the mechanical strength and thermal stability of separators. [28,29] However, the major component of previously reported SiO 2 -modified separators is still polymer, thus only offering limited improvement in battery performance. Alternatively, inorganic separators have been developed by directly coating SiO 2 particles on the surface of electrodes. [30] Despite the great promise, the much higher density of SiO 2 (≈2.2 g cm −3 ) relative to polyolefin (0.90-0.97 g cm −3 ) restricts its commercial application in high energy density batteries. Besides, the increased tortuosity with the use of SiO 2 particles can increase the ionic diffusion path length, [31] which may lead to the concentration Commercial polymeric separators in lithium-ion batteries (LIBs) typically suffer from limited porosity, low electrolyte wettability, and poor thermal and mechanical stability, which can degrade the battery performance especially at high current densities. Here, the design of hierarchically porous, ultralight silica membranes as separator for high-performance LIBs is reported through the assembly of hollow mesoporous silica (HMS) particles on the cathode surface. The rich mesopores and ...

Highly ordered and interconnected mesoporous carbon is designed to simultaneously address the challenges in the cathode and anode in lithium metal–sulfur full cells.

Low-bandgap covalent organic frameworks (COFs) emerge as one of the most intriguing conjugated polymers for the development of electronic devices, while they often lack desirable electron affinity, thereby compromising the activity and stability in electrochemical transformation. Here, we report an n-type semiconducting two-dimensional (2D) COF, featuring a low bandgap (1.36 eV) and strong electron affinity (4.41 eV) as well as high crystallinity and porosity. The columnar stacking array of the benzobisthiadiazole moiety in 2D COFs plays a critical role in elevating electroactivity. It not only leads to the outstanding electrical conductivity and air stability upon reductive doping but also enables the boost of transformation kinetics for polysulfides on the separators of lithium−sulfur batteries causing a higher capacity and better cycling performance. The design strategy underpins the versatile development of electroactive COF materials with desirable electronic properties and promotes their applicability in energy storage and electronics.

Layered mesostructured graphene, which combines the intrinsic advantages of planar graphene and mesoporous materials, has become interestingly important for energy storage and conversion applications. Here, an interlayer‐confined molecular assembly method is presented for constructing all‐graphitic multilaminate membranes (MMG⊂rGO), which are composed of monolayer mesoporous graphene (MMG) sandwiched between reduced graphene oxide (rGO) sheets. Hybrid assembly of iron‐oleate complexes and organically modified GO sheets enables the preferential assembly of iron‐oleate precursors at the interlayer space of densely stacked GO, driven by the like‐pair molecular van der Waals interactions. Confined pyrolysis of iron‐oleate complexes at GO interlayers leads to close‐packed, carbon‐coated Fe3O4 nanocrystal arrays, which serve as intermediates to template the subsequent formation of MMG⊂rGO membranes. To demonstrate their application potentials, MMG⊂rGO membranes are exploited as dual‐functional interlayers to boost the performance of Li–S batteries by concurrently suppressing the shuttle of polysulfides and the growth of Li dendrites. This work showcases the capability of molecular‐based hybrid assembly for synthesizing multilayer mesostructured graphene with high packing density and its use in electrochemical energy applications.