High-energy-density lithium-sulfur (Li-S) batteries hold promise for next-generation portable electronic devices, but are facing great challenges in rational construction of high-performance flexible electrodes and innovative cell configurations for actual applications. Here we demonstrated an all-MXene-based flexible and integrated sulfur cathode, enabled by three-dimensional alkalized TiC MXene nanoribbon (a-TiC MNR) frameworks as a S/polysulfides host (a-TiC-S) and two-dimensional delaminated TiC MXene (d-TiC) nanosheets as interlayer on a polypropylene (PP) separator, for high-energy and long-cycle Li-S batteries. Notably, an a-TiC MNR framework with open interconnected macropores and an exposed surface area guarantees high S loading and fast ionic diffusion for prompt lithiation/delithiation kinetics, and the 2D d-TiC MXene interlayer remarkably prevents the shuttle effect of lithium polysulfides via both chemical absorption and physical blocking. As a result, the integrated a-TiC-S/d-TiC/PP electrode was directly used for Li-S batteries, without the requirement of a metal current collector, and exhibited a high reversible capacity of 1062 mAh g at 0.2 C and enhanced capacity of 632 mAh g after 50 cycles at 0.5 C, outperforming the a-TiC-S/PP electrode (547 mAh g) and conventional a-TiC-S on an Al current collector (a-TiC-S/Al) (597 mAh g). Furthermore, the all-MXene-based integrated cathode displayed outstanding rate capacity of 288 mAh g at 10 C and long-life cyclability. Therefore, this proposed strategy of constructing an all-MXene-based cathode can be readily extended to assemble a large number of MXene-derived materials, from a group of 60+ MAX phases, for applications such as various batteries and supercapacitors.

Graphene and graphene oxide (GO), as wonder materials, have penetrated nearly every field of research. One of their most attractive features is the functionality and assembly of graphene or GO, in which they can be considered to be chemically functionalized building blocks for creating unconventional porous graphene materials (PGMs) that not only combine the merits of both porous materials and graphene, but also have major advantages over other porous carbons for specific applications. The chemistry and approaches for functionalizing graphene and GO are first introduced, and typical procedures for pore creation (e.g., in-plane pores, 2D laminar pores, and 3D interconnected pore assemblies), self-assembly, and tailoring mechanisms for PGMs to highlight the significance of precise control over the pore morphology and pore size are summarized. Because of their unique pore structures, with different morphologies and intriguing properties, PGMs serve as key components in a variety of applications such as energy storage, electrocatalysis, and molecular separation. Finally, the challenges relating to PGMs from the understanding of chemical self-assembly to specific applications are discussed, and promising solutions on how to tackle them are presented. This provides an insightful outlook for the future development of the chemistry and applications of PGMs.