High Li + transference number electrolytes have long been understood to provide attractive candidates for realizing uniform deposition of Li + . However, such electrolytes with immobilized anions would result in incomplete solid electrolyte interphase (SEI) formation on the Li anode because it suffers from the absence of appropriate inorganic components entirely derived from anions decomposition. Herein, a boron-rich hexagonal polymer structured all-solid-state polymer electrolyte (BSPE+10% LiBOB) with regulated intermolecular interaction is proposed to trade off a high Li + transference number against stable SEI properties. The Li + transference number of the as-prepared electrolyte is increased from 0.23 to 0.83 owing to the boron-rich cross-linker (BC) addition. More intriguingly, for the first time, the experiments combined with theoretical calculation results reveal that BOB − anions have stronger interaction with B atoms in polymer chain than TFSI − , which significantly induce the TFSI − decomposition and consequently increase the amount of LiF and Li 3 N in the SEI layer. Eventually, a LiFePO 4 |BSPE+10% LiBOB|Li cell retains 96.7% after 400 cycles while the cell without BC-resisted electrolyte only retains 40.8%. BSPE+10% LiBOB also facilitates stable electrochemical cycling of solid-state Li-S cells. This study blazes a new trail in controlling the Li + transport ability and SEI properties, synergistically.
High-temperature oxidation behavior of dense amorphous boron-rich Si 2 B 1-4 C 2 N monoliths in flowing air was studied in detail. The oxidation products are those of amorphous silica and cristobalite that control the diffusion of oxygen inward. Oxygen diffusion leads to a dense and passivating scale, which acts as a barrier to oxygen. Amorphous boron-rich monoliths oxidize through a classical parabolic manner. The amorphous nature, three-layers structure of oxide scale and varying chemical bonds are primarily responsible for the oxidation resistance with respect to the nano monoliths. The increase in boron content is revealed to weaken the oxidation resistance of the amorphous Si 2 B 1-4 C 2 N monoliths.
Zhong-Xia Wang,Lei Hu,Xiao-Qiong Li,Yi-Lei Jia,Ting Wang,Wei Wang
Exploring the ultrahigh quantum efficiency of a carbon-based probe via a green and simple technique, and utilisation of its sensing ability for highly bioactive molecule detection is still highly challenging. Herein, we prepared a novel boron-enriched rice-like homologous carbon nanoclusters (BRCNs) with an ultrahigh quantum efficiency of ∼51.5% by introduction of a conjugated structure attached to the CN bond and an electron-withdrawing boron active centre. Unexpectedly, the BRCNs obtained showed a stable dispersion of rice-like carbon nanograins, composed of small carbon dot assembled nanoclusters with an average diameter size of ∼30 nm, and containing boron units of ∼24.68 at%. What's exciting is that the BRCNs obtained exhibited an “on–off–on” three-state emission with the addition of an hydroxyl radical (OH˙) and its antioxidants. Thus, two distinctive fluorescent responses for OH˙ and antioxidants based on the BRCN probe had been developed, and the mechanism has been determined using TEM, XPS, FT-IR, FL, UV-vis spectrophotometry, UPS and fluorescent lifetimes. The OH˙, generated from the Fenton's reagent, preferentially attack the electron-deficient vacancy p orbit of the boron atom in the surface of the BRCNs, which results in the boron atom being easily substituted/attacked by OH˙, and leading to spontaneous aggregation induced quenching (AIQ) due to the existence of a strong intermolecular hydrogen bond between denatured BRCNs. Furthermore, the proposed method was also successfully applied to monitor endogenous OH˙ generation in HeLa cells by confocal imaging, which could be used for elucidating OH˙-induced oxidative damage to biological tissues and proteins.