Coupling NiCoP bimetallic phosphide nanoparticles with alkali-induced 3D crinkled Ti3C2 effectively enhances the structural stability and improved reaction kinetics of anodes for SIBs.

Silicon is attracting enormous attention due to its theoretical capacity of 4200 mAh g−1 as an anode for Li‐ion batteries (LIBs). It is of fundamental importance and challenge to develop low‐temperature reaction route to controllably synthesize Si/Ti3C2 MXene LIBs anodes. Herein, a novel and efficient strategy integrating in situ orthosilicate hydrolysis and a low‐temperature reduction process to synthesize Si/Ti3C2 MXene composites is reported. The hydrolysis of tetraethyl orthosilicate leads to homogenous nucleation and growth of SiO2 nanoparticles on the surface of Ti3C2 MXene. Subsequently, SiO2 nanoparticles are reduced to Si via a low‐temperature (200 °C) reduction route. Importantly, Ti3C2 MXene not only provides fast transfer channels for Li+ and electrons, but also relieves volume expansion of Si during cycling. Moreover, the characteristics of excellent pseudocapacitive performance and high conductivity of Ti3C2 MXene can synergistically contribute to the enhancement of energy storage performance. As expected, Ti3C2/Si anode exhibits an outstanding specific capacity of 1849 mAh g−1 at 100 mA g−1, even retaining 956 mAh g−1 at 1 A g−1. The low‐temperature synthetic route to Si/Ti3C2 MXene electrodes and involved battery‐capacitive dual‐model energy storage mechanism has potential in the design of novel high‐performance electrodes for energy storage devices.

The novel PDDA-NPCNs/Ti3C2 hybrids via an electrostatic attraction self-assembly approach effectively accelerate reaction kinetics and improve electrochemical performance as PIBs anodes.

Unique layered Ti3C2/Ni–Co–Al layered double hydroxide (LDH) heterostructures alternatively stacked with molecular-level nanosheets are for the first time synthesized by a facile liquid-phase cofeeding and electrostatic attraction heteroassemble strategy between negatively charged Ti3C2 and positively charged Ni–Co–Al-LDH nanosheets. The molecular-level Ti3C2/Ni–Co–Al-LDH heterostructures possessing the merits of both conductive and pseudocapacitive components can show greatly enhanced dynamic behavior in Faradaic reaction, which is significant for obtaining a high power density. Electrons penetrate in Ti3C2 layers, while ions diffuse rapidly along two-dimensional galleries, displaying the shortest diffusion pathway and highest efficiency for charge transfer. The Ti3C2/Ni–Co–Al-LDH heterostructure exhibits a specific capacitance of 748.2 F g–1 at current density of 1 A g–1, showing an enhanced rate capacity. Importantly, a maximum energy density of 45.8 Wh kg–1 is obtained when Ti3C2/Ni–Co–Al-LDH acts as the positive electrode for an all-solid-state flexible asymmetric supercapacitor. The results indicate that molecular-level heterotructure is a promising candidate for future high-energy supercapacitors.

While research interest in aqueous batteries has surged due to their intrinsic low cost and high safety, the practical application is plagued by the restrictive capacity (less than 600 mAh g −1 ) of electrode materials. Sulfur-based aqueous batteries (SABs) feature high theoretical capacity (1672 mAh g −1 ), compatible potential, and affordable cost, arousing ever-increasing attention and intense efforts. Nonetheless, the underlying electrochemistry of SABs remains unclear, including complicated thermodynamic evolution and insufficient kinetics metrics. Consequently, multifarious irreversible reactions in various application systems imply the systematic complexity of SABs. Herein, rather than simply compiling recent progress, this Perspective aims to construct a theory-to-application methodology. Theoretically, attention has been paid to a critical appraisal of the aqueous-S-related electrochemistry, including fundamental properties evaluation, kinetics metrics with transient and steady-state analyses, and thermodynamic equilibrium and evolution. To put it into practice, current challenges and promising strategies are synergistically proposed. Practically, the above efforts are employed to evaluate and develop the device-scale applications, scilicet flow-SABs, oxide-SABs, and metal-SABs. Last, chemical and engineering insights are rendered collectively for the future development of high-energy SABs.