Hierarchical Spatial Confinement Unlocking the Storage Limit of MoS₂ for Flexible High-Energy Supercapacitors

Abstract

Molybdenum sulfide (MoS 2 ) is a promising electrode material for supercapacitors; however, its limited Mo/S edge sites and intrinsic inert basal plane give rise to sluggish active electronic states, thus constraining its electrochemical performance. Here we propose a hierarchical confinement strategy to develop ethylene molecule (EG)-intercalated Co-doped sulfur-deficient MoS 2 (Co-EG/S V -MoS 2 ) for efficient and durable K-ion storage. Theoretical analyses suggest that the intercalation-confined EG and lattice-confined Co can enhance the interfacial K-ion storage capacity while reducing the K-ion diffusion barrier. Experimentally, the intercalated EG molecules with mildly reducing properties induced the creation of sulfur vacancies, expanded the interlayer spacing, regulated the 2H−1T phase transition, and strengthened the structural grafting between layers, thereby facilitating ion diffusion and ensuring structural durability. Moreover, the Co dopants occupying the initial Mo sites initiated charge transfer, thus activating the basal plane. Consequently, the optimized Co-EG/S V -MoS 2 electrode exhibited a substantially improved electrochemical performance. Flexible supercapacitors assembled with Co-EG/S V -MoS 2 delivered a notable areal energy density of 0.51 mW h cm −2 at 0.84 mW cm −2 with good flexibility. Furthermore, supercapacitor devices were integrated with a strain sensor to create a self-powered system capable of real-time detection of human joint motion.

Oxygen Vacancy and Heterostructure Modulation of Co2P/Fe2P Electrocatalysts for Improving Total Water Splitting

“…Among the studied nonprecious metal electrocatalysts, various low-cost materials have been shown to serve as efficient and stable electrocatalysts. For example, transition metal oxides (hydroxides), sulfides, carbides, nitrides, phosphides, etc. − Although these materials can exhibit excellent HER or OER performance in alkaline or acidic media, the hydrolysis performance is not excellent when the same material is placed in an electrolyte as the cathode and anode, respectively. Transition metal phosphides (TMPs) are considered as a catalytic material with potential applications due to their similar electronic structure to Pt, excellent electrochemical activity, and unique physicochemical properties. , Although TMPs have shown excellent performance in water electrolysis, they still cannot meet the production intensity of industrialized production with high current and long time.…”

Heterostructured grafting of NiFe-layered double hydroxide@TiO2 for boosting photoelectrochemical cathodic protection

“…9–12 Among the semiconductors used in PECCP systems, one-dimensional n-type TiO 2 nanostructures, such as nanorods, have received the most attention because of their enhanced charge transport along their longitudinal direction, light-trapping characteristics, and large specific surface area. 13–16 However, TiO 2 has a high OER reaction energy barrier and possesses limited surface active sites. Heterostructure engineering represents an advanced strategy to address this issue because the energy alignment and interfacial electronic coupling between different components drive the transfer of photoexcited charges, and the secondary material can introduce more OER active sites.…”

An effective strategy to construct α-MoO3//PPy toward high-energy-density asymmetric supercapacitors

“…For the anode of ASCs, the currently studied potential pseudocapacitive materials include WO 3 , 18 MoS 2 , 19,20 Nb 2 O 5 , 21 MoO 3 , 22 Fe 2 O 3 , 23 Co 3 O 4 24 and V 2 O 5 . 25 Among which MoO 3 emerges as an exceptionally favorable candidate as its two-dimensional layered structure can facilitate the insertion and removal of electrolyte ions between the layers.…”