Yijun Yang

Beijing Jiaotong University | NJTU · School of Physical Science and Engineering

Room temperature and solution-processible spin-light emitting diodes (spin-LEDs) are of practical importance since electronic spins act as information carriers for circularly polarized electroluminescence (CP-EL) generation. The recent boost of quasi-2D chiral hybrid perovskites (CHPs) has gained unprecedented attention because of the possible spin...

The development of free‐standing and foldable electrodes with excellent electrochemical performance is paramount for flexible electronic devices. However, the silicon‐based free‐standing anodes lack a straightforward preparation process. Herein, we successfully designed a hierarchical Si@C/CNFs composite material by combining hydrothermal and elect...

The development of a methodology for synthesizing value‐added urea (CO(NH2)2) via a renewable electricity‐driven C−N coupling reaction under mild conditions is highly anticipated. However, the complex catalytic active sites that act on the carbon and nitrogen species make the reaction mechanism unclear, resulting in a low efficiency of C−N coupling...

The development of a methodology for synthesizing value‐added urea (CO(NH2)2) via a renewable electricity‐driven C‐N coupling reaction under mild conditions is highly anticipated. However, the complex catalytic active sites that act on the carbon and nitrogen species make the reaction mechanism unclear, resulting in a low efficiency of C‐N coupling...

Charging LiCoO2 to high voltages yields alluring specific capacities, yet the deleterious phase‐transitions lead to significant capacity degradation. Herein, this study demonstrates a novel strategy to stabilize LiCoO2 at 4.6 V by doping with Er and Mg at the Li‐site and Co‐site, respectively, which is different from the traditional method of dopin...

Platinum‐based single‐atom catalysts (Pt1 SACs) can significantly improve the catalytic activity for propane dehydrogenation (PDH) because of their elevated atomic utilization. However, maintaining the high‐temperature stability of the Pt1 species is of utmost importance. To answer the key question: Hydroxy‐ or chlorine‐anchored Pt1 single atoms in...

The catalytic activities are generally believed to be relevant to the electronic states of their active center, but understanding this relationship is usually difficult. Here, we design two types of catalysts for electrocatalytic urea via a coordination strategy in a metal–organic frameworks: CuIII-HHTP and CuII-HHTP. CuIII-HHTP exhibits an improve...

Cycling lithium cobalt oxide (LiCoO2) to a potential higher than 4.35 V (vs Li⁺/Li) can obtain an enticing capacity, but suffers from inferior structural stability. Herein, an ingenious Li‐deintercalation/doping strategy is developed to synthesize the lanthanide‐doped LiCoO2 (lanthanide (Ln) = praseodymium, neodymium, samarium, europium, gadolinium...

Supported vanadium catalysts are commonly investigated in industrial propane dehydrogenation (PDH) but still remain a great challenge to achieve high propylene selectivity and productivity. Here, Ni species were adopted to regulate the micro-structure of V2O5 supported by γ-Al2O3 via incipient wetness impregnation method. The Ni-doped vanadium cata...

Since sluggish Li+ desolvation leads to severe capacity degradation of carbon anodes at subzero temperatures, it is urgently desired to modulate electron configurations of surface carbon atoms toward high capacity for Li-ion batteries. Herein, a carbon-based anode material (O-DF) was strategically synthesized to construct the Riemannian surface wit...

Propane dehydrogenation to propylene, one of the most significant compounds in the chemical industry, has attracted tremendous attention worldwide. A series of V doped graphitic carbon nitride composites (V-g-C3N4) were synthesized via a combination of thermal polymerization of urea and thermal decomposition of NH4VO3. After doping VOx species, the...

Silicon suboxide (SiOx) is considered a promising substitute for silicon (Si) anode materials in lithium-ion batteries due to its high specific capacity (>2200 mAh g⁻¹) and improved cycling performance. However, its volume expansion (∼200%) and low conductivity cannot be ignored. Here, inspired by earbuds, we design and mass synthesize (240 g h⁻¹)...

Li-ion batteries (LIBs) suffer from severe capacity recession at subzero temperatures due to the dramatic increase in charge transfer resistance induced by the sluggish desolvation process. In this paper, we report on by using the weakly coordinating molecule as electrolyte (1M LiPF6 in EC: DMC: PC=1:1:1 vol%), the cell with MoS2 as the model elect...

Li6.4La3Zr1.4Ta0.6O12 (LLZTO), a typical oxidizing ceramic solid electrolyte of excellent lithium-ion conductivity, is considered as a promising candidate for next-generation high-energy-density solid-state lithium metal batteries (SSLMBs). However, great challenges, such as the unexpected growth of lithium dendrites and the excessive resistance of...

The importance of the solid electrolyte interphase (SEI) layer for enhanced Li-ion storage has been well established, but primary understanding of the chemical components and structure of SEI layer on MXene-based electrodes remains incomplete. Here, we characterized the morphology and components of SEI layer on Ti3C2Tx and Ti3C2Tx/Fe2O3 electrode m...

Atomistic exploration of Li⁺ diffusion behaviors in electrodes of lithium-ion batteries (LIBs) has been documented to be an effective strategy to uncover Li⁺ storage mechanisms and to guide the design of promising electrode materials. In this work, we prepared two different types of SnO2 nanorods-graphene hybrids with anchored (A-SnG) and sandwiche...

The ideal anode materials for lithium-ion batteries require high specific capacity, excellent electrochemical stability and robust mechanical properties. Silicon nanowires (Si NWs) may be a suitable anode material. However, the anisotropic expansion of Si NWs depending on crystallographic orientation frequently leads to their fractures and poor sta...

Silicon (Si) is the most promising anode material for new generation high-performance Lithium-ion batteries (LIBs), but the colossal volume expansion and poor conductivity limit its applications. In this work, we develop a mussel-pearl-inspired Si-embedded carbon/graphite composite (Si/C composite) via a two-step process of ball-milling and subsequ...

Chemical bonding has been regarded as an effective modification strategy to enhance the electrochemical performance of MXenes for Li-ion batteries (LIBs). However, the in-depth mechanism, especially concentrating on the regulation of chemical bond, is rarely explored. Herein, we design an atomically dispersed Fe in Ti3C2Tx MXene (Fe-Ti3C2Tx) by a d...

Silicon (Si) anode materials have been extensively studied due to high capacity and abundant reserves. Herein, inspired by the Li + ‐inert components, we design a novel silicon/iron silicide nanoparticles (Si/FeSi 2 NPs) prepared by thermal plasma to achieve stress‐releasing effect. The Si/FeSi 2 NPs is composed of Si and FeSi 2 which exhibits supe...

Inorganic–organic hybrid perovskite solar cells (PSCs) have stirred up a new research spree in the field of photovoltaics due to its high photoelectric conversion efficiency and simple preparation process. In recent years, the research of inorganic–organic hybrid PSCs has been widely reported, among which FA⁺/Cs⁺ PSCs are especially outstanding. Ho...

While surface charge state of co-catalysts plays a critical role for boosting photocatalysis, the study on surface charge regulation via their precise structure control, remains extremely rare. Herein, a metal-organic framework (MOF)-stabilized bimetallic Pd@Pt nanoparticles (NPs), which feature adjustable Pt coordination environment and the contro...

Developing new types of rechargeable batteries with high energy densities and low cost have received increasing attentions, aiming to reduce the dependence on high-priced lithium. Beyond Li-ion batteries, the potential alternatives including Na-ion batteries, Li-S batteries and Li-air batteries have been investigated recently, which are required to...

Doping in carbon anodes can introduce active sites, usually leading to extra capacity in Li-ion batteries (LIBs), but the underlying reasons have not been uncovered deeply. Herein, the dodecahedral carbon framework (N-DF) with a low nitrogen content (3.06 wt %) is fabricated as the anode material for LIBs, which shows an extra value of 298 mA h g–1...

It is highly important to develop ultrastable electrode materials for Li-ion batteries (LIBs), especially in the low temperature. Herein, we report Fe³⁺-stabilized Ti3C2Tx MXene (donated as T/F-4:1) as the anode material, which exhibits an ultrastable low-temperature Li-ion storage property (135.2 mA h g⁻¹ after 300 cycles under the current density...

Energy crisis and global warming due to excessive CO2 emissions are the two major challenges of the world. Conversion of CO2 into useful fuels along with rechargeable metal-air batteries and water splitting is one way to combat the energy crisis, which is bottlenecked due to the lack of multifunctional electrocatalyst. Herein simple but multifuncti...

Traditional lithium-ion batteries (LIBs) suffer from tremendous electrochemical performance fading at low temperatures (LT). This work reports a novel MoS2/C hybrid electrode that shows excellent LT performance as LIB anodes. At −20 °C, it delivers a stable discharge capacity as high as 854.3 mAh g⁻¹ which is 72.8% of that at room temperature (RT)....

Polyhedral carbons from zeolitic imidazolate frameworks (ZIFs) have been studied as anode materials for lithium-ion batteries, because their topological feature enabled ideal research objects. However, the similarities and differences of lithium-ion storage behavior between ZIFs polyhedral carbons have not been systematically studied. Here we synth...

Synthesis of a thin layer of perovskite with less pinholes and defects is vital for the construction of a high-performance perovskite solar cell (PSC). We report on an oriented attachment strategy to fabricate a black phase CsPbI3 highly-oriented quasi-single-crystalline microstructures film for constructing a mesoporous PSC device with enhanced po...

The unsatisfied low-temperature performance of anode materials in Li-ion batteries (LIBs) remains an unsolved challenge along the development of LIBs. In particular, the inferior Li-ion diffusion kinetics under lower temperature limits the capacity and durability of LIB. Extensive researches have confirmed that a novel structural design of the anod...

Heteroatom doping in nanomaterials can import new active sites and promote catalytic activity. Here we report that Mn-doped Co3O4 nanorods (Mnx-Co3O4) via substituting Mn3+ (t2g3-eg1) for Co3+ (t2g6-eg0), exhibit ~100% yield for 4-methyl benzyl alcohol dehydrogenation catalysis at 60 °C and no decay (8 cycles), compared with only 1.4% of activity f...

Graphite-like coated silicon ([email protected]) material has been shown to be only partly useful in addressing the technological problems of high-capacity Si anodes in lithium ion batteries (LIBs). This is because of inevitable and large internal stresses in a [email protected] structure induced by instantaneously explosive expansion of Si upon li...

The near-infrared-IIb (NIR-IIb) (1,500–1,700 nm) window is ideal for deep-tissue optical imaging in mammals, but lacks bright and biocompatible probes. Here, we developed biocompatible cubic-phase (α-phase) erbium-based rare-earth nanoparticles (ErNPs) exhibiting bright downconversion luminescence at ~1,600 nm for dynamic imaging of cancer immunoth...

Insights into the real catalytic active site (or sites) of the promising oxygen evolution reaction (OER) catalysts is significant for further developing high-performance catalysts. Spinel cobalt oxide (Co3O4), with both Co2+ and Co3+, has been widely studied as an efficient non-precious OER catalyst. However, controversial results still exist towar...

Organic-inorganic hybrid perovskites simultaneously possess strong spin-orbit coupling (SOC) and structure inversion asymmetry, establishing a Rashba effect to influence light emission and photovoltaics. Here, we use mechanical bending as a convenient approach to investigate the Rashba effect through SOC in perovskite (MAPbI3-xCl x ) films by elast...

Silicon-carbon (Si-C) hybrids have been proven to be the most promising anodes for the next-generation lithium ion batteries (LIBs) due to their superior theoretical capacity (~4200 mAhg-1). However, it is still a critical challenge to apply this material for the commercial LIB anodes, because of the large volume expansion of Si, unstable solid-sta...

The practical application of Si‐based materials has been widely impeded by the poor electrochemical cycling stability. Here, inspired by the compact cladding and close connection structure of the beans, we design an efficient buffering bean‐structured material of Si/C framework as a stable anode for Li‐ion storage. By a simple ball‐milling process,...

Compared with their 3D counterparts, layered 2D Ruddlesden-Popper perovskites (2D RPPs) with the formula of (A′) 2 A n-1 Pb n X 3n+1 exhibit improved photo and moisture stability. To develop flexible single-crystalline electronics and wearable devices, cost-effective growth of large-area single crystals of 2D RPPs with large lateral size, ultrathin...

Carbon composite products with different structures have been developed and used as anode for lithium-ion batteries due to the superior elasticity of carbon, which can keep the morphology integrity of the electrode materials in the process of the multiple cycles. Herein, a novel structure of nanosheets-in-nanotube Co 3 O 4 /carbon arrays is fabrica...

Lithium ion batteries (LIBs) process performance fading and safety concerns at low temperature (LT) prohibit their application in cold climates. The alloy-type electrodes demonstrate great potentials in stable and dendrite-free anodes at LT. Herein, we report a temperature-dependent Li-storage performance in Al-based nanoporous alloy anode. The nan...

Inspired by a folded protein, the multistage structural MoS2 are designed as the advanced anode materials for lithium‐ion batteries (LIBs). The density functional theory (DFT) calculations are initially performed, demonstrating that an ideal primary structure (P‐MoS2) has the saw‐tooth‐like edges terminated by Mo atoms and the desired secondary str...

Spinel NiCo2X4 (X = O or S), comprising two geometrical cobalt ions: Co2+ in tetrahedral site (Co2+Td) and Co3+ in octahedral site (Co3+Oh), has widely evaluated as a promising pseudocapacitor electrode material. Previous literatures mainly demonstrated that much higher specific capacitance of NiCo2S4 than that of NiCo2O4 was ascribed to the higher...

Precise control of crystal orientations and macroscopic morphology of a perovskite crystal is crucial for various optoelectronic applications relying on charge carrier transport tuning along exposed crystal facets. Here, taking methylammonium lead bromide (CH3NH3PbBr3) as an example, and employing a novel crystal facet engineering method, we succes...

While converting carbon dioxide (CO2) into value-added carbon products by electrolyzing offers a promising approach to mitigate global warming and store energy, poor selectivity and stability of catalysts still impede this conversion. Single-atom catalyst exhibits exceptional selectivity for CO2 electroreduction reaction in response to inhibiting h...

Functional fabrics with various unique properties are necessary for making fantastic superior costumes just like superhero suit in Marvel Comics, which are not only dreams of boys but also emerging textiles to facilitate human life. Based on the inspiration of a phenomenon in an extracurricular experiment for kids, we develop a biofabrication strat...

Dodecahedral nanocarbons with highly curving concave faces are synthesized via a one-step directly pyrolysis strategy. When tested as anodes in lithium-ion batterries (LIBs), the concaved dodecahedral carbons (CDCs) show much enhanced capacity (~ 2 times) and improved rate capability (603 mAh g-1 at 2000 mA g-1), when compared with the perfect ones...

As one of promising cathode materials, NiS2 delivers ultrahigh theoretic capacity of 870 mAh/g. However, it suffers from huge capacity fading during the multiple cycles because of the close formation enthalpy between NiS2 and other nickel sulphides (Ni3S4, Ni3S2 and NiS) and the large volumetric expansion during charging. To overcome these drawback...

Two-dimensional nanostructures may effectively be utilized as electrode materials for lithium/sodium-ion batteries to enhance the energy and power densities and cycling stability, and to satisfy the increasing demands of electrical vehicles and power stations. This review introduces the “geometry-driven” concept to illuminate the mechanisms related...

Lithium‐ion batteries (LIBs) have been widely applied in portable electronics (laptops, mobile phones, etc.) as one of the most popular energy storage devices. Currently, much effort has been devoted to exploring alternative high‐capacity anode materials and thus potentially constructing high‐performance LIBs with higher energy/power density. Here,...

Electrocatalytic hydrogen evolution reaction (HER) in alkaline solution is hindered by its sluggish kinetics toward water dissociation. Nickel-based catalysts, as low-cost and effective candidates, show great potentials to replace platinum (Pt)-based materials in the alkaline media. The main challenge regarding this type of catalysts is their relat...

Huge volume expansion of Sn-based anode during Li-insertion leads to instability of the electrodes and degrades the electrochemical performances and thus prohibited their practical applications. Herein we propose a new “digging holes” approach to develop a three dimensional CuSn electrode, in which the active Sn adhere to conductive Cu framework. T...

The development of rechargeable batteries with high performance is considered to be a feasible way to satisfy the increasing needs of electric vehicles and portable devices. It is of vital importance to design electrodes with high electrochemical performance and to understand the nature of the electrode/electrolyte interfaces during battery operati...

Photodetectors based on two-dimensional (2D) nanostructures have led to a high optical response, and a long photocarrier lifetime because of spatial confinement effects. Since the discovery of graphene, many different 2D semiconductors have been developed and utilized in the ultrafast and ultrasensitive detection of light in the ultraviolet, visibl...

Engineering of the optical, electronic, and magnetic properties of hexagonal boron nitride (h-BN) nanomaterials via oxygen doping and functionalization has been envisaged in theory. However, it is still unclear as to what extent these properties can be altered using such methodology because of the lack of significant experimental progress and syste...

The main challenge associated with sodium-ion battery (SIB) anodes is a search for novel candidate materials with high capacity and excellent rate capability. The most commonly used and effective route for graphene-based anode design is the introduction of in-plane "hole" defects via nitrogen-doping; this creates a spacious reservoir for storing mo...

Hydrogen evolution reaction (HER) from water electrolysis is an attractive technique developed in recent years for cost-effective clean energy. Although considerable efforts have been paid to create efficient catalysts for HER, the development of an affordable HER catalyst with superior performance under mild conditions is still highly desired. In...

A novel carbon structure, highly branched homogeneous-N-doped graphitic (BNG) tubular foam, is designed via a novel N, N-dimethylformamide (DMF)-mediated chemical vapor deposition method. More structural defects are found at the branched portions as compared with the flat tube domains providing abundant active sites and spacious reservoirs for Li(+...

Integration of two-dimensional (2D) nanomaterials and their composites into energy storage devices, especially rechargeable batteries, offers opportunities to timely tackle the challenges of ever growing clean and sustainable energy demands. Therefore, it is crucial to design hybrid 2D electrode materials for high performance rechargeable batteries...

Better tissue penetration and lower overheating problems mean 808 nm near-infrared laser excited upconversion nanoparticles (UCNPs) have potential in bioapplications. Dumbbell-like structured NaYF4:Yb/Er@NaNdF4:Yb nanoparticles are fabricated in this work and applied in photodynamic therapy (PDT). The epitaxial growth along the c axis attributed to...

As the most promising anode material for sodium-ion batteries (SIBs), elemental phosphorus (P) has recently gained a lot of interest due to its extraordinary theoretical capacity of 2596 mAh/g. The main drawback of a P anode is its low conductivity and rapid structural degradation caused by the enormous volume expansion (>490%) during cycling. Here...

Carbon doping has been widely applied to modify TiO2 to improve photocatalytic activity and initiate visible light activity. Using oleylamine wrapped TiO2 nanomaterials as precursor, carbon doped TiO2 photocatalysts have been synthesized by control of heating ramp rates and temperatures in air. Optical absorption of all these photocatalysts are ext...

Photocatalytic water splitting into hydrogen, a renewable and environmental friendly alternative energy resource, offers a promising way to solve the increasingly urgent energy crisis. We prepare here a series of TiO2-carbon hybrid nanomaterials by heating oleylamine wrapped ultrathin TiO2 nanosheets at different temperatures in air or inert atmosp...

Ultrathin two-dimensional nanosheets have been widely studied because of their peculiar properties and promising applications. As a typical layered material, successful exfoliation of freestanding ultrathin lepidocrocite (γ-FeOOH) nanosheets from the bulk material has not been reported to date. Herein, we report a facile synthetic route to prepare...

Nd(3+) -sensitized quenching-shield sandwich structure upconversion nanoparticles are designed by J. Yao, Y. Ma, Y. Zhao, and co-workers on page 2831. The transition layer in this unique structure is essential to eliminate the photon-quenching effect caused by Nd(3+) -doping, and simultaneously bridge the energy transfer from the sensitizer to the...

By using 1,5-pentanediol as a capping and structure directing agent, ultrathin Eu2O3 nanosheets (<1 nm) have been synthesized and assembled into a layered structure. The lateral dimensions of the nanosheets can be tuned by simply controlling the reaction time. These layered structures exhibit a strong quantum size effect due to the extremely small...

We have demonstrated a new and facile bottom-up protocol for the effective synthesis of oval-shaped iron oxide/ethylene glycol (FeOx /EG) mesostructured nanosheets. Deprotonated ethylene glycol molecules are intercalated into iron oxide layers to form an interlayer distance of 10.6 Å. These materials display some peculiar magnetic properties, such...

A series of polyimides (PIs) with side chains were fabricated from 6-(4-phenylphenoxy)hexyl-3,5-diaminobenzoate of various ratios with 4,4′-oxydianiline and 4,4′-oxydiphthalic anhydride. After PI alignment, films were directly fluorinated using a 10 vol% fluorine/nitrogen mix. The pretilt angle of liquid crystals on the PI films is much improved to...

RAFT dispersion copolymerization was carried out using methyl methaerylate (MMA) and tripropylene glycol diacrylate (TPGDA) as comonomers and ethanol/water as a mixed solvent and S-l-dodecyl-S′-( α, α-dimethyl- α"-aceticacid)trithiocarbonate as a chain transfer agent to inhibit the occurrence of gelation. The long nucleation period and gelation wer...