Nowadays, the development of high-voltage LiCoO₂ (lithium cobalt oxide, LCO) cathodes has attracted the widespread attention from both the academic and industry fields. Among the multiple concerns, researches on the surface issues would provide the most effective performance optimization pathway for the synthesis of high-voltage LCO. In this work, the issues of high-voltage LCO, including the phase transitions and crack formation, the oxygen redox related issues and side reactions, as well as the surface structure degradation, have been systematically reviewed. Then, we further clarify the surface modulations, and the interplay between the surface modulation and electrolyte tuning. Finally, we propose our prospects for developing the more advanced LCO cathodes, including the low-cost and high-quality manufacturing, designing suitable LCO cathodes in some extreme conditions (such as high-temperature, high-rate charging, low temperature, etc.), and achieving stabilized capacity release of about 220 mAh·g^–1 of LCO, etc. We hope that this work can serve as a reference to promote the development and application of high-voltage LCO in future.

Silver (Ag) paste is widely used in semiconductor metallization, especially in silicon solar cells. Ag powder is the material with the highest proportion in Ag paste. The morphology and structure of Ag powder are crucial which determine its characteristics, especially for the sintering activity. In this work, a simple method was developed to synthesize a type of microcrystalline spherical Ag particles (SP-A) with internal pores and the structural changes and sintering behavior were thoroughly studied by combining ultra-small-angle X-ray scattering (USAXS), small-angle X-ray scattering (SAXS), in-situ heating X-ray diffraction (XRD), focused ion beam (FIB), and thermal analysis measurement. Due to the unique internal pores, the grain size of SP-A is smaller, and the coefficient of thermal expansion (CTE) is higher than that of traditional solid Ag particles. As a result, the sintering activity of SP-A is excellent, which can form a denser sintered body and form silver nanoparticles at the Ag–Si interface to improve silver silicon contact. Polycrystalline silicon solar cell built with SP-A obtained a low series resistance (R_s) and a high photoelectric conversion efficiency (PCE) of 19.26%. These fill a gap in Ag particle structure research, which is significant for the development of high-performance electronic Ag particles and efficient semiconductor devices.

Lithium (Li) metal is one of the most promising anodes for next-generation energy storage systems. However, the Li dendrite formation and unstable solid-electrolyte interface (SEI) have hindered its further application. Lithium nitrate (LiNO₃) is extensively used as an effective electrolyte additive in ether-based electrolytes to improve the stability of lithium metal. Nevertheless, it is rarely utilized in carbonate electrolytes due to its low solubility. Here, a novel gel polymer electrolyte (GPE) consisting of poly(vinylidene fluoride) (PVDF), poly(methyl methacrylate) (PMMA), poly(ethylene oxide) (PEO) with LiNO₃ additive is proposed to solve this issue. In this GPE, polyether-based PEO serves as a matrix for dissolving LiNO₃ which can be decomposed into a fast Li-ion conductor (Li₃N) in conventional carbonate electrolytes to enhance the stability and Li⁺ conductivity of the SEI film. As a result, dendrite formation is effectively suppressed, and a significantly improved average Coulombic efficiency (CE) of 97.2% in Li-Cu cell is achieved. By using this novel GPE coupled with Li anode and LiNi_0.5Mn_0.3Co_0.2O₂ (NMC532), excellent capacity retention of 94.1% and high average CE of over 99.2% are obtained after 200 cycles at 0.5 C. This work presents fresh insight into practical modification strategies on high-voltage Li metal batteries.

Graphite as a positive electrode material of dual ion batteries (DIBs) has attracted tremendous attentions for its advantages including low lost, high working voltage and high energy density. However, very few literatures regarding to the real-time observation of anion intercalation behavior and surface evolution of graphite in DIBs have been reported. Herein, we use in situ atomic force microscope (AFM) to directly observe the intercalation/de-intercalation processes of PF₆^- in graphite in real time. First, by measuring the change in the distance between graphene layers during intercalation, we found that PF₆^- intercalates in one of every three graphite layers and the intercalation speed is measured to be 2 μm·min^-1. Second, graphite will wrinkle and suffer structural damages at high voltages, along with severe electrolyte decomposition on the surface. These findings provide useful information for further optimizing the capacity and the stability of graphite anode in DIBs.

Moore's law is approaching its physical limit. Tunneling field-effect transistors (TFETs) based on 2D materials provide a possible scheme to extend Moore's lawdown to the sub-10-nm region owing to the electrostatic integrity and absence of dangling bonds in 2D materials. We report an ab initio quantum transport study on the device performance of monolayer (ML) black phosphorene (BP)TFETs in the sub-10-nm scale (6–10 nm). Under the optimal schemes, the ML BP TFETs show excellent device performance along the armchair transport direction.The on-state current, delay time, and power dissipation of the optimal sub-10-nm ML BP TFETs significantly surpass the latest International Technology Roadmap for Semiconductors (ITRS) requirements for high-performance devices. The subthreshold swings are 56–100 mV/dec, which are much lower than those of their Schottky barrier and metal oxide semiconductor field-effect transistor counterparts.

Semiconducting monolayer (ML) blue phosphorene (BlueP) shares similar stability with ML black phosphorene (BP), and it has recently been grown on an Au surface. Potential ML BlueP devices often require direct contact with metal to enable the injection of carriers. Using ab initio electronic structure calculations and quantum transport simulations, for the first time, we perform a systematic study of the interfacial properties of ML BlueP in contact with metals spanning a wide work function range in a field effect transistor (FET) configuration. ML BlueP has undergone metallization owing to strong interaction with five metals. There is a strong Fermi level pinning (FLP) in the ML BlueP FETs due to the metal-induced gap states (MIGS) with a pinning factor of 0.42. ML BlueP forms n-type Schottky contact with Sc, Ag, and Pt electrodes with electron Schottky barrier heights (SBHs) of 0.22, 0.22, and 0.80 eV, respectively, and p-type Schottky contact with Au and Pd electrodes with hole SBHs of 0.61 and 0.79 eV, respectively. The MIGS are eliminated by inserting graphene between ML BlueP and the metal electrode, accompanied by a transition from a strong FLP to a weak FLP. Our study not only provides insight into the ML BlueP–metal interfaces, but also helps in the design of ML BlueP devices.