Lithium–sulfur (Li–S) batteries are considered as one of the most promising next‐generation rechargeable batteries owing to their high energy density and cost‐effectiveness. However, the sluggish kinetics of the sulfur reduction reaction process, which is so far insufficiently explored, still impedes its practical application. Metal–organic frameworks (MOFs) are widely investigated as a sulfur immobilizer, but the interactions and catalytic activity of lithium polysulfides (LiPs) on metal nodes are weak due to the presence of organic ligands. Herein, a strategy to design quasi‐MOF nanospheres, which contain a transition‐state structure between the MOF and the metal oxide via controlled ligand exchange strategy, to serve as sulfur electrocatalyst, is presented. The quasi‐MOF not only inherits the porous structure of the MOF, but also exposes abundant metal nodes to act as active sites, rendering strong LiPs absorbability. The reversible deligandation/ligandation of the quasi‐MOF and its impact on the durability of the catalyst over the course of the electrochemical process is acknowledged, which confers a remarkable catalytic activity. Attributed to these structural advantages, the quasi‐MOF delivers a decent discharge capacity and low capacity‐fading rate over long‐term cycling. This work not only offers insight into the rational design of quasi‐MOF‐based composites but also provides guidance for application in Li–S batteries.

Lithium–Sulfur Batteries A “Quasi‐MOF” nanosphere is introduced by Yongguang Zhang, Xin Wang, Zhongwei Chen, and co‐workers in article number 2105541 as an efficient and durable sulfur electrocatalyst toward accelerated sulfur reduction reaction. The reversible de‐ligandation/ligandation of this Quasi‐MOF over the course of the electrochemical process endows its with excellent catalytic activity and remarkable durability. Attributed to these structural advantages, the Quasi‐MOF delivers a decent discharge capacity and low‐capacity fading rate over long‐term cycling.

Sodium‐ion batteries (SIBs) have attracted much attention for their advantages of high operating voltage, environmental friendliness and cost‐effectiveness. However, the intrinsic defects of anode materials (such as poor electrical conductivity, sluggish kinetics, and large volume changes) hinder them from meeting the requirements for practical applications. Herein, a Nb2O5@carbon nanoreactor containing both a O–Nb–C heterointerface and oxygen vacancies (Nb2O5‐x@MEC) as an anode material is designed to drive SIBs toward extraordinary capacity and ultra‐long cycle life. The heterostructured nanoreactor both effectively immobilizes defective Nb2O5 by forming O‐Nb‐C heterointerface and offers homogeneous dispersion of Nb2O5 with desirable content to prevent their agglomeration. In addition, vast active interfaces, favored electrolyte infiltration, and a well‐structured ion–electron transportation channel are enabled by the framework, improving sodium ion storage and enhancing redox reaction kinetics. The enhancement brought by spatial confinement, defect implantation and heterointerface design give the composites a highly reversible sodiation–desodiation process and remarkable structural stability. By virtue of these superiorities, Nb2O5‐x@MEC delivers excellent performance, i.e., high areal capacity over 1.1 mAh cm‐2, admirable rate capability up to 20 A g‐1, and ultra‐long cycling performance over 5000 cycles, holding great promise for utilization in practically viable SIBs.

Sodium‐Ion Batteries In article number 2103716, Xin Wang, Zhongwei Chen and co‐workers propose a novel heterostructured nanoreactor which exhibits inlaid ultrafine oxygen deficient nanosized Nb2O5 inside mesoporous carbon via construction of a O‐Nb‐C heterointerface. The material serves as an anode for sodium‐ion batteries to realize a fast and durable sodiation/desodiation process. Moreover, the synergistic incorporation of the O‐Nb‐C heterointerface and defects further enhances electron transportation and enables highly reversible structure evolution over the course of electrochemical process.

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