Thiocyanate Coordination Regulates the Interlayer Ammonium Ion Storage Structure of Molybdenum Disulfide

Abstract

Aqueous ammonium ion storage utilizes the intercalation and coordination diffusion mechanisms of NH₄⁺ within the host material, resulting in a low-cost, high-safety energy storage device. However, the capacity of the NH₄⁺ storage hosts, represented by layered materials, is mainly limited by the limited interlayer size and coordination sites. Here, a strategy is proposed to enhance NH₄⁺ storage by utilizing nonmetallic ions with long-chain structures to regulate the interlayer spacing and coordination activity of MoS₂. Atomic-level electron microscopy, chemical reactions, and theoretical simulations revealed that SCN^– was successfully intercalated into MoS₂ and coordinated with S atoms to construct an interlayer network. The intercalation of SCN^– provides sufficient space and abundant hydrogen-bonding sites. This work effectively solves the dilemma of traditional layered materials in NH₄⁺ storage and demonstrates the broad prospects of interlayer coordination engineering strategies for energy storage devices.