Heteroatom doping is an effective way to generate oxygen vacancies and improve the electrochemical properties of materials. However, the heteroatom doping process is more complicated and it is difficult to ensure the simultaneous generation of defects. In this work, TiO2 quantum dots/graphene aerogel composites were synthesized via a simple hydrothermal method. The N and S atoms were successfully incorporated by electron beam irradiation, and a large number of defects were introduced. The effects of irradiation dose on the doping amount, elemental morphology, and electrochemical properties of the compounds were further studied. The synergistic effect between graphene’s double-layer capacitance and TiO2 quantum dots’ pseudocapacitance, as well as the introduction of heteroatomic doping and defects, is beneficial to improve the electrochemical performance of the material. When used as an electrode material for supercapacitors, NT-NSG-140 at an irradiation dose of 140 kGy shows the best electrochemical performance. At a high current density of 5 A g–1, the NT-NSG-140 maintains a capacity of 127.8 F g–1. This work provides an environmentally friendly, simple, and efficient method for designing high-performance materials containing heteroatoms.

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Construction of three-dimensional (3D) Cu current collectors is a promising approach to improving the stability of Li metal batteries. Although many efforts have yielded fruitful results, most of them are complex, subtle, and involve high energy consumption. We present a facile chemical fabrication of a 3D current collector which offers the advantages of rapid and low cost assembly by Cu fibers. A skeleton host with a high surface activity can significantly suppress Li dendrite growth and improve the electrochemical deposition behavior of Li. Up to 7 mAh cm−2 of Li can be plated in the 3D Cu current collector without dendrite generation. Cells based on 3D Cu collectors achieved a high average Coulombic efficiency of 97% over 160 cycles (50 cycles for planar Cu) and a long cycle life of more than 900 h at 1 mA cm−2. Moreover, full cells assembled with Li-plated 3D Cu anodes and LiFePO4 cathodes displayed impressive cycling stability and rate capability at a high rate of 4C.

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The tribological behaviour of a rare earth naphthenate (REN) as a lubricant oil additive i n VG26 white oil and the complexes of R E N and organo-sulphur or organo-phosphate compounds have been evaluated with a four-ball friction and wear tester. The chemical features and elemental composition of the boundary lubricating film were examined by means of Auger electron spectroscopy (AES) and X-ray photoelectron spectrometry (PS). The results show that R E N exhibits good antiwear, loadcarrying, and friction-reducing properties in the base stock.When 2.0% R E N is added, the wear-scar diameter value reduces to 54.7% of that for the base stock aione and the maximum non-seizure load increases 2.95 times. .4 synergistic effect is found for the load-carrying capability of t!ae complex of R E N and organo-sulphur while poor Compatibility is exhibited for the complex of R E N and organo-phosphate. The analytical results of AES and XPS indicate that the good performance of R E N is attributable to the formation of a boundary lubricating film mainly composed of naphthenic acid, rare earth oxide, and complexes of rare earth metals, which is formed on a rubbed surface when lubricated by oil containing the R E N additive.

The anode electrochemical performance of lithium-ion batteries (LIBs) depends mainly on the structural stability of the electrode material and its conductivity, and its energy storage mechanism is mainly derived from the Faraday charge transfer that occurs around the electrode surface and the Faraday pseudocapacitance. Due to the high theoretical specific capacity of transition metal sulfides (TMS) and the mechanical stability and high conductivity of carbon cloth (CC), the strategy of growing TMS in situ in CC can simultaneously improve reversibility, structural stability, and conductivity. In this work, hierarchical 3D-Zn-ZIF-on-2D-Co-ZIF precursors are grown in situ on CC by a strategy called MOF-on-MOF, and the ZnS/CoS2/CC stable framework is obtained by sulfuration. The interfacial electron transfer mechanism was explored by ultraviolet photoelectron spectroscopy, and the synergistic interaction between ZnS and CoS2 in ZnS/CoS2/CC was further elaborated. Specifically, the work functions of ZnS and CoS2 are 15.9 and 16.6 eV, respectively, and the corresponding Fermi energy levels are 5.32 eV for ZnS and 4.62 eV for CoS2. Therefore, after doping with ZnS, electrons will be transferred and enriched from the ZnS surface to the CoS2 surface to accelerate the reduction process of CoS2, and this plays such a decisive part during the electrochemical reaction. Thereby, the charge enrichment and rapid transfer at the ZnS/CoS2/CC interface facilitates the Faraday reaction. As a result, ZnS/CoS2/CC exhibits an outstanding electrochemical performance as an anode material for LIBs, with a capacity of up to 1644.7 mA h g–1 after 160 cycles at a high current density of 1 A g–1.

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