Advances and perspectives on one-dimensional nanostructure electrode materials for potassium-ion batteries

Transition metal dichalcogenides (TMDs) show great potential as anodes for potassium‐ion batteries (PIBs) due to their high theoretical capacity and relatively low working potential. However, usually the conversion mechanism seriously hinders the long‐term cycle stability for PIBs due to the huge structural change. Herein, the synthesis of a class of ultrathin metallic 2H‐phase NbS2 nanosheets with large expanded interlayer spacing of 0.65 nm and high conductivity for boosting the potassium ion storage is reported. It is demonstrated that the as‐prepared NbS2 nanosheets show an unexpected intercalation mechanism for potassium ion storage, which is conceptually different from the well‐known intercalation‐conversion mechanism of typical TMDs. As a consequence, the ultrathin NbS2 nanosheets deliver superior rate capability (205.5 mAh g−1 at ultrahigh current density of 10 A g−1) and outstanding long‐term cycling performance (169.5 mAh g−1 at 5 A g−1 after 4000 cycles with a very low decay rate of 0.005% per cycle), representing the most stable TMD‐based anode materials for PIBs. Ex situ measurements and first‐principles calculations disclose and interpret that NbS2 nanosheets store potassium ions through only the intercalation mechanism without any conversion reaction taking place in the potassiation/depotassiation process, which highly improves the structural stability of electrode materials, hence promoting the long‐term cycle performance.

Ultrathin Metallic NbS2 Nanosheets with Unusual Intercalation Mechanism for Ultra‐Stable Potassium‐Ion Storage

Recent Progress of Novel Non-Carbon Anode Materials for Potassium-Ion Battery

Recent advances in dual- and multi-responsive nanomedicines for precision cancer therapy.

Understanding the dynamics of stimuli-sensitive self-assembled nanomaterials is crucial for their potential applications, however, it is relatively difficult to quantitatively probe the dynamics using conventional analytical techniques because of the low sensitivity and selectivity of these techniques. In this research, TEMPO-containing nonamphiphilic copolymers are synthesized and highly sensitive, selective and non-destructive electron spin resonance (ESR) spectroscopy is applied to study their dynamics in stimuli-sensitive self-assembled nanostructures in different microenvironments. ESR spectroscopy reveals the structural changes of the smart supramolecular nanoparticles (SNPs) in their controlled assemblies by observing the molecular-level interactions. In order to obtain the dynamical evidence, several spectroscopic parameters such as rotational correlation time, hyperfine splitting constant, intensity increase/decrease and anisotropy parameters are determined from the ESR spectra. The stimuli-sensitivity and dynamics strongly depend on the SNPs’ microenvironment correlated to several chemical and physiological parameters such as radical concentration, pH, redox agent, temperature, polarity and viscosity. The results provide quantitative insights into the interface of the supramolecular assemblies. The nanoparticles showed good biocompatibility confirmed by the hemolysis test and the MTT assay. Furthermore, proof-of-concept experiments were carried out to demonstrate the SNPs’ stimuli-sensitive performance as a hydrophobic anticancer drug nanocarrier. This effort can be used to design other colloidal nano-platforms for the potential application in cancer treatment. 

Stimuli-sensitivity and dynamics in the self-assembly structure of TEMPO-containing nonamphiphilic nanoparticles and their triggering hydrophobic drug release

Potassium ion batteries (KIBs) have attracted great attention recently as a promising large-scale energy storage system by virtue of the bountiful K resource and low standard hydrogen potential of K+/K. However, their development is hindered by the limited capacity and inferior cycling stability resulting from the large size of K+. Here, a unique vanadium sulfide@carbon nanorod is designed and synthesized for high-performance KIBs. Thanks to the hybrid structure, abundant active sites, fast ion diffusion, and capacitive-like electrochemical behavior of the electrode, the anode exhibits a large specific capacity (468 mA h g-1 after 100 cycles at 0.1 A g-1), predominant rate performance (205 mA h g-1 at 5 A g-1), and impressive cycling stability (171 mA h g-1 for 4000 cycles at 3 A g-1). Furthermore, the constructed KIB full cell demonstrates 229 mA h g-1 at 0.5 A g-1 and 86% capacity retention over 300 cycles.

One-Step Construction of V5S8 Nanoparticles Embedded in Amorphous Carbon Nanorods for High-Capacity and Long-Life Potassium Ion Half/Full Batteries.

Metal phosphides with a high theoretical capacity and low redox potential have been proposed as promising anodes for potassium-ion batteries (PIBs). A reasonable configuration design and introduction of a hollow structure with adequate internal void spaces are effective strategies to overcome the volume expansion of metal phosphides in potassium-ion batteries. Herein, we report a cage-confinement pyrolysis strategy to obtain hollow nanocage-structured nitrogen/phosphorus dual-doped carbon-coated copper phosphide (Cu3P/CuP2@NPC), which exhibits a high initial charge capacity (409 mA h g-1 at 100 mA g-1) and an outstanding cycle performance (100 mA h g-1 after 5000 cycles at 1000 mA g-1) as an anode material for PIBs. The novel hollow nanocage structure could prevent volume expansion during cycling and reduce the electron/ion diffusion distance. Besides, the nitrogen/phosphorus dual-doped carbon-coated layer could promote electronic conductivity. In situ X-ray diffraction (XRD) measurements are conducted to study the potassiation/depotassiation mechanism of Cu3P/CuP2@NPC and reveal the structure stability during the cycle process, which further proves that the design ideas of the conductive carbon layer and the hollow structure with adequate internal void spaces are successful.

Cage-Confinement Pyrolysis Strategy to Synthesize Hollow Carbon Nanocage-Coated Copper Phosphide for Stable and High-Capacity Potassium-Ion Storage.

Artemisinin compounds have shown satisfactory safety records in anti-malarial clinical practice over decades and have revealed value as inexpensive anti-tumor adjuvant chemotherapeutic drugs. However, the rational design and precise preparation of nanomedicines based on the artemisinin drugs are still limited due to their non-aromatic and fragile chemical structure. Herein, a bioinspired coordination-driven self-assembly strategy was developed to manufacture the artemisinin-based nanoprodrug with a significantly increased drug loading efficacy (∼70 wt %) and decreased preparation complexity compared to conventional nanodrugs. The nanoprodrug has suitable size distribution and robust colloidal stability for cancer targeting in vivo. The nanoprodrug was able to quickly disassemble in the tumor microenvironment with weak acidity and a high glutathione concentration, which guarantees a better tumor inhibitory effect than direct administration and fewer side effects on normal tissues in vivo. This work highlights a new strategy to harness a robust, simplified, organic solvent-free, and highly repeatable route for nanoprodrug manufacturing, which may offer opportunities to develop cost-effective, safe, and clinically available nanomedicines.

Jinwei Tu

Papers

One-Step Construction of V5S8 Nanoparticles Embedded in Amorphous Carbon Nanorods for High-Capacity and Long-Life Potassium Ion Half/Full Batteries.

Cage-Confinement Pyrolysis Strategy to Synthesize Hollow Carbon Nanocage-Coated Copper Phosphide for Stable and High-Capacity Potassium-Ion Storage.

Bioinspired Microenvironment Responsive Nanoprodrug as an Efficient Hydrophobic Drug Self-Delivery System for Cancer Therapy.