Reversible Single-Crystal-to-Single-Crystal Transformations between Nanoscale 2D Nanosheets and 3D Metal-Organic Frameworks.

Single-crystal-to-single-crystal (SCSC) transformations provide more possibilities for phase transitions, which have attracted great attention in crystal engineering. In this paper, we report a series of reversible SCSC transformations between nanoscale two-dimensional layered double hydroxide (LDH) crystals and three-dimensional metal-organic framework crystals. They can proceed not only in solution systems but also on the surface of solid-state polyacrylonitrile films and fibers. Specifically, reversible SCSC transformations can be carried out between nanoscale ZIF-67 and Co-LDH. The Co-LDH nanomaterials displayed excellent oxygen evolution reaction performance. This work has good universality and scalability, which provides a novel avenue for the synthesis of crystal materials and is of great significance for the recycling of resources.

CoSe2 nanoparticles anchored on dual 1D carbon nanotubes/N-doped carbon nanofibers as high-performance anodes for sodium-ion storage.

Transition metal chalcogenides (TMCs) have been widely explored and utilized in sodium-ion battery (SIB) anodes owing to their unique advantages, such as high theoretical specific capacity and low cost. However, their inherent defects, such as low electronic conductivity and severe volume expansion, seriously limit the further development of TMC-based anodes. Here, a novel composite material of CoSe2 nanoparticles (NPs) encapsulated in a dual one-dimensional (1D) carbon composite structure (CoSe2@CNTs/N-CNFs) was designed deliberately. Carbon nanotubes (CNTs) were grown in situ on the surface of carbon nanofibers (CNFs) with eco-friendly ethanol as the carbon source, while electrospun polyacrylonitrile (PAN) fibers were pyrolyzed to form nitrogen-doped nanofibers. It is noted that the wrapping with the composite carbon structure greatly improved the stability of CoSe2 NPs and solved its inherent defects as an anode material. When assembled into a half-cell, the CoSe2@CNTs/N-CNFs electrode exhibited outstanding sodium storage performance with a reversible specific capacity of 442 mA h g-1 after 100 cycles at 0.1 A g-1, as well as excellent rate performance, and the discharge specific capacity still reached 265 mA h g-1 even after 2000 cycles at a high current density of 5 A g-1. This study shows a new way to build a novel carbon substrate and TMC composite sodium storage material with low cost.

Mechanism of High-Tech Enterprises' Technological Practices Affected by the Split Fault of Knowledge Innovation Network.

Knowledge innovation ability is the source of value realization of high-tech enterprises, and the acquisition of high-value knowledge is important. Taking knowledge as the intermediary variable, knowledge field activity and knowledge fermentation as mediating variables, and knowledge mobilization and knowledge network position transition as moderating variables, the conceptual model and theoretical analysis framework of the impact mechanism of knowledge innovation network fragmentation fault on technology practices is constructed and the moderated mediating effect model is derived. Taking high-tech enterprises as empirical samples, 538 valid questionnaires were obtained online and offline and the nonpercentile bootstrap method based on deviation correction was used to empirically investigate the influence mechanism and transmission path of knowledge innovation network fragmentation fault on high-tech enterprises' technological practices. The empirical results show that the main effect of knowledge innovation network fragmentation fault on high-tech enterprise technology practices is significant. Knowledge field activity and knowledge fermentation play a differential mediating role in knowledge innovation network split fault and Technology Convention. Knowledge field activity and knowledge fermentation play a partial mediating role in knowledge innovation network split fault and Technology Convention. Knowledge mobilization partially moderates the split fault of knowledge innovation network and technological practices. Knowledge mobilization positively moderates the positive effect of split fault of knowledge innovation network on technological practices and significantly positively moderates the mediating effect of knowledge field activity and knowledge fermentation, resulting in the moderated mediating effect. Knowledge network location transition plays a part of moderating role in knowledge innovation network split fault and Technology Convention. Knowledge network location transition positively moderates the positive impact of knowledge innovation network split fault on Technology Convention and significantly positively moderates the mediating role of knowledge field activity and knowledge fermentation, resulting in a moderated mediating effect. Knowledge innovation network split fault, knowledge field activity and knowledge fermentation, knowledge mobilization and knowledge network location transition, and the combination of technological practices can be the antecedents of promoting technological practices in high-tech enterprises. Through the research on the mechanism of knowledge innovation network split fault in the technological practices of high-tech enterprises, the connotation of knowledge innovation network split fault is enriched, the influencing factors of technological practices are clarified, and the value-added knowledge is promoted and has guiding and reference significance for the innovation knowledge acquisition and competitiveness improvement of high-tech enterprises.

The Influence Mechanism of Knowledge Network Allocation Mechanism on Knowledge Distillation of High-Tech Enterprises.

Increasing global development competition highlights the value of knowledge innovation ability of high-tech enterprises. In order to acquire innovative knowledge, the mediating variables of knowledge field activity and knowledge stock ranking are selected; the moderating variables of knowledge resource pooling and knowledge evolution are adopted to construct the conceptual model and theoretical analysis framework of the influence mechanism of knowledge network arrangement mechanism on knowledge distillation; the moderating mediating effect model is derived; and the influence mechanism of knowledge network allocation mechanism on knowledge distillation of high-tech enterprises is clarified. 531 valid questionnaires were obtained online and offline, and non-percentile bootstrap based on deviation correction was used to empirically investigate the influence mechanism and transmission path of knowledge network allocation mechanism on knowledge distillation of high-tech enterprises. The empirical results show that the main effect of knowledge network pairing on knowledge distillation of high-tech enterprises is significant. The results show that knowledge field activity and knowledge stock ranking play a differential intermediary role in knowledge network allocation and knowledge distillation, knowledge field activity plays a partial intermediary role in knowledge network allocation and knowledge distillation, and knowledge stock ranking plays a partial intermediary role in knowledge network allocation and knowledge distillation. Pooling knowledge resources positively moderates the positive effect of knowledge network allocation mechanism on knowledge distillation and significantly positively moderates the mediating effect of knowledge field activity, and there is a moderated mediating effect derived from it. However, there is no significant moderating effect on knowledge stock ranking between knowledge network allocation mechanism and knowledge distillation. Knowledge evolution positively moderates the positive effect of knowledge network allocation mechanism on knowledge distillation, significantly positively moderates the mediating effect of knowledge field activity, and derives the moderated mediating effect. However, there is no significant moderating effect on knowledge stock ranking between knowledge network allocation mechanism and knowledge distillation. This paper makes an empirical study on the effect of knowledge allocation mechanism on knowledge distillation, enriches the connotation and application scope of knowledge distillation, defines the driving factors and formation mechanism of knowledge distillation, and further promotes the knowledge value and knowledge appreciation of high-tech enterprises. It has guiding and reference significance in the acquisition of innovation knowledge and the promotion of competitiveness of high-tech enterprises.

Pseudocapacitance-boosted ultrafast and stable Na-storage in NiTe2 coupled with N-doped carbon nanosheets for advanced sodium-ion half/full batteries.

Developing high-rate and durable anode materials for sodium-ion batteries (SIBs) is still a challenge because of the larger ion radius of sodium compared with the lithium ion during charge-discharge processes. Herein, NiTe2 coupled with N-doped carbon (NiTe2/NC) hexagonal nanosheets has been fabricated through a solvothermal and subsequent carbonisation strategy. This unique hexagonal nanosheet structure offers abundant active sites and contact area to the electrolyte, which could shorten the Na+ diffusion path. The heterostructured N-doping carbon improves the electrochemical conductivity and accelerates the kinetics of Na+ transportation. Electrochemical analysis shows that the charge-discharge process is controlled by the pseudocapacitive behavior thus leading to high-rate capability and long lifespan in half batteries. As expected, high capacities of 311 mA h g-1 to 217 mA h g-1 at 5 A g-1 to 10 A g-1 are maintained after 800 and 1200 cycles, respectively. Furthermore, a full battery equipped with a Na3V2(PO4)2O2F cathode and a NiTe2/NC anode offers a maximum energy density of 104 W h kg-1 and a maximum power density of 9116 W kg-1. The results clearly show that the NiTe2/NC hexagonal nanosheet with superior Na storage properties is an advanced new material for energy storage systems.