Engineering Nanoclay Edges to Construct Effective Polysulfide‐Trapping Interface for Markedly Enhanced Electrochemical Energy Storage

Lithium–sulfur (Li–S) batteries suffer from the infamous lithium polysulfides (LPSs) shuttle effect, which generates reduced utilization of active materials and polysulfide‐corrosion‐accelerated lithium dendrite, ultimately resulting in poor capacity and cycling stability. While various natural clays have demonstrated effective adsorption for LPSs, there is no consensus on the adsorption mechanisms and active sites. Inspired by the distinct acid–base chemistry of clay basal and edge surfaces, we designed a capsule‐shaped silicate clay (H‐ATP‐N 2 ) that is rich in protonated edge hydroxyl groups (‐OH 2+ ). The synthesis involved a two‐step process: first, microwave‐assisted acid treatment was used to efficiently activate the surface of fibrous attapulgite. Next, N 2 plasma etching was applied to further enrich the material with the ‐OH 2 + . These specific methods were chosen to optimize the activation and functionalization of attapulgite, enhancing its ability to serve as a highly effective polysulfide‐trapping interface for improved electrochemical energy storage. Compared with the surface hydroxyl sites, the ‐OH 2 + act as Lewis acid sites to accept lone electron pairs from LPSs, thereby exhibiting a stronger interaction to successfully inhibit the shuttle effect. With the protonated edge hydroxyl groups in attapulgite dominating LPSs adsorption via a Lewis acid–base adsorption mechanism, the H‐ATP‐N 2 cathodes deliver a 1139.9 mAh g −1 capacity at 0.1 C, and a reversible capacity of 808.6 mAh g −1 after 500 cycles at 0.5 C with an ultralow capacity decay rate of 0.04% per cycle, which have surpassed the vast majority of reported clay‐based cathodes.