Lithium–sulfur
batteries possess the merits of low cost
and high theoretical energy density but suffer from the shuttle effect
of lithium polysulfides and slow redox kinetics of sulfur. Herein,
novel Co0.85Se nanoparticles embedded in nitrogen-doped
carbon nanosheet arrays (Co0.85Se/NC) were constructed
on carbon cloth as the self-supported host for a sulfur cathode using
a facile fabrication strategy. The interconnected porous carbon-based
structure of the Co0.85Se/NC could facilitate the rapid
electron and ion transfer kinetics. The embedded Co0.85Se nanoparticles can effectively capture and catalyze lithium polysulfides,
thus accelerating the redox kinetics and stabilizing sulfur cathodes.
Therefore, the Co0.85Se/NC-S cathode could maintain a stable
cycle performance for 400 cycles at 1C and deliver a high discharge
specific capacity of 1361, 1001, and 810 mAh g–1 at current densities of 0.1, 1, and 3C, respectively. This work
provides an efficient design strategy for high-performance lithium–sulfur
batteries with high energy densities.
Environment-friendly flexible Cu2ZnSn(S,Se)4 (CZTSSe) solar cells show great potentials for indoor photovoltaic market. Indoor lighting is weak and multi-directional, thus the researches of photovoltaic device structures, techniques and performances face new challenges. Here, we design symmetrical bifacial CZTSSe solar cells on flexible Mo-foil substrate to efficiently harvest the indoor energy. Such devices are fabricated by double-sided deposition techniques to ensure bifacial consistency and save cost. We report 9.3% and 9% efficiencies for the front and back sides of the flexible CZTSSe solar cell under the standard sun light. Considering the indoor environment, we verify weak-light response performance of the devices under LED illumination and flexibility properties after thousands of bending. Bifacial CZTSSe solar cells in parallel achieve the superposition of double-sided output current from multi-directional light, significantly enhancing the area utilization rate. The present results and methods are expected to expand indoor photovoltaic applications.
Lithium (Li) has garnered considerable attention as an alternative anodes of next‐generation high‐performance batteries owing to its prominent theoretical specific capacity. However, the commercialization of Li metal anodes (LMAs) is significantly compromised by non‐uniform Li deposition and inferior electrolyte–anode interfaces, particularly at high currents and capacities. Herein, a hierarchical three‐dimentional structure with CoSe2‐nanoparticle‐anchored nitrogen‐doped carbon nanoflake arrays is developed on a carbon fiber cloth (CoSe2–NC@CFC) to regulate the Li nucleation/plating process and stabilize the electrolyte–anode interface. Owing to the enhanced lithiophilicity endowed by CoSe2–NC, in situ‐formed Li2Se and Co nanoparticles during initial Li nucleation, and large void space, CoSe2–NC@CFC can induce homogeneous Li nucleation/plating, optimize the solid electrolyte interface, and mitigate volume change. Consequently, the CoSe2–NC@CFC can accommodate Li with a high areal capacity of up to 40 mAh cm–2. Moreover, the Li/CoSe2–NC@CFC anodes possess outstanding cycling stability and lifespan in symmetric cells, particularly under ultrahigh currents and capacities (1600 h at 10 mA cm−2/10 mAh cm−2 and 5 mA cm−2/20 mAh cm−2). The Li/CoSe2–NC@CFC//LiFePO4 full cell delivers impressive long‐term performance and favorable flexibility. The developed CoSe2–NC@CFC provides insights into the development of advanced Li hosts for flexible and stable LMAs.
An aggregation-enhanced emission active luminogen named as sodium 4,4'4″-(3,4-diphenyl-1H-pyrrole-1,2,5-triyl)tribenzoate (DP-TPPNa) with propeller construction was synthesized and developed as a "turn on" fluorescent probe for in situ quantitation of albumin in blood serum. The DP-TPPNa fluorescence intensity was linearly correlated with the concentration of two serum albumins, bovine serum albumin (BSA) and human serum albumin (HSA), in pure PBS buffer in the ranges of 2.18-70 and 1.68-100 μg/mL, respectively. The detection limits were as low as 2.18 μg/mL for BSA and 1.68 μg/mL for HSA. The response time of fluorescence to serum albumin (SA) was very short (below 6 s), which achieved real-time detection. It also showed high selectivity to SA because other components in serum barely interfere with the detection of DP-TPPNa to SA, enabling in situ quantitative detection of SA without isolation from serum. DP-TPPNa was successfully applied for the quantitative detection of BSA in fetal bovine serum. The mechanism of fluorescent turn-on behavior was elucidated utilizing an unfolding process induced by guanidine hydrochloride, which revealed a capture process via selective hydrophobic interaction and hydrogen bonding between luminogen and SA.
Lithium
is deemed as the anticipated anode for the next-generation
energy storage system. Nevertheless, its commercial application is
greatly hindered by the uneven deposition and volume expansion in
the process of lithium plating and stripping. Here, a three-dimensional
lithiophilic current collector with in situ grown
CuO nanowire arrays on Cu foam has been demonstrated to effectively
ameliorate the above problems. Beneficial from the large specific
surface area and lithiophilicity properties, CuO nanowire arrays prominently
diminish the local current density and nucleation overpotential, resulting
in uniform lithium deposition. Moreover, the optimized anode exhibits
a prolonged lifespan for more than 280 cycles at 0.5 mA cm–2 and a high coulombic efficiency of 95.5% for over 150 cycles at
3 mA cm–2 in an assembled half cell, which is maintained
steadily for 540 h in a symmetric cell with good capacity retention
capabilities in a full cell. This facile approach provides a feasible
strategy to realize stable lithium deposition and a high-performance
lithium metal anode.
Multicomponent reactions (MCRs) facilitate the rapid and diverse construction of molecular scaffolds with modularity and step economy. In this work, engagement of boronic acids as carbon nucleophiles culminates in a Passerini-type three-component coupling reaction towards the synthesis of an expanded inventory of α-hydroxyketones with skeletal diversity. In addition to the appealing features of MCRs, this protocol portrays good functional group tolerance, broad substrate scope under mild conditions and operational simplicity. The utility of this chemistry is further demonstrated by amenable modifications of bioactive products and pharmaceuticals as well as in the functionalization of products to useful compounds.
A new chiral Brønsted acid, generated in situ from a chiral phosphoric acid boron (CPAB) complex and water, was successfully applied to asymmetric indole reduction. This “designer acid catalyst”, which is more acidic than TsOH as suggested by DFT calculations, allows the unprecedented direct asymmetric reduction of C2‐aryl‐substituted N‐unprotected indoles and features good to excellent enantioselectivities with broad functional group tolerance. DFT calculations and mechanistic experiments indicates that this reaction undergoes C3‐protonation and hydride‐transfer processes. Besides, bulky C2‐alkyl‐substituted N‐unprotected indoles are also suitable for this system.
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