Trimethylsilyl Borate Research Articles

Virtual screening of borate derivatives as high-performance additives in lithium-ion batteries

Tris (trimethylsilyl) borate (TMSB) is well known as a novel cathode electrolyte interphase (CEI)-forming additive for improving the cycle performance of LiCoO2/graphite lithium-ion batteries. We suggest five borate derivatives as promising candidates for CEI-forming additives resulting in higher performance than TMSB as determined via first-principles density functional calculations of oxidation potentials, reduction potentials, and F− binding affinities. This computational screening protocol provides a faster method for the development of new CEI-forming electrolyte additives in lithium-ion batteries.

Effect of tris(trimethylsilyl)borate on the high voltage capacity retention of LiNi0.5Co0.2Mn0.3O2/graphite cells

This study demonstrates that tris(trimethylsilyl)borate (TMSB) additive in the electrolyte can dramatically improve the cycling performance of LiNi0.5Co0.2Mn0.3O2/graphite cell at higher voltage operation. And the effects of this additive are characterized by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). In the voltage range of 3.0–4.4 V, LiNi0.5Co0.2Mn0.3O2/graphite cell with TMSB in the electrolyte retains about 92.3% of its initial capacity compared to the cell without additive in the electrolyte that retains only 28.5% of its initial capacity after 150 cycles, showing the promising prospect of TMSB at higher voltage. The enhanced cycling performance is attributed to the thinner film originated from TMSB on the LiNi0.5Co0.2Mn0.3O2 and the combination of TMSB with PF6− and F− in the electrolyte, which not only protects the undesirable decomposition of EC solvents but also results in lower interfacial impedance.

Tris(trimethylsilyl) borate as an electrolyte additive to improve the cyclability of LiMn2O4 cathode for lithium-ion battery

In order to overcome severe capacity fading of LiMn2O4 cathode lithium-ion battery, tris(trimethylsilyl) borate (TMSB) is used as an electrolyte additive. With 0.5 wt% TMSB addition into the electrolyte (EC/DMC with 1 M LiPF6), the capacity retention is significantly improved at both room temperature and 55 °C. The effects of the TMSB on the LiMn2O4 electrode are investigated via a combination of cyclability, capacity retention of high temperature storage, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Based on these results, it is suggested that the improved cyclability of the cells containing the TMSB additive is mainly originated from the participation in the formation of solid electrolyte interface (SEI) on the surface of electrode, the dissolution of LiF out of the SEI and the enhancement of cyclability of Li anode.

Tris(trimethylsilyl) borate as electrolyte additive to improve performance of lithium-ion batteries

Tris(trimethylsilyl) borate (TMSB) used as new electrolyte additive to improve performance of LiFePO 4 based lithium-ion battery is investigated in this paper. The effects of the TMSB on the LiFePO 4 electrode are investigated via a combination of electrochemical impedance spectroscopy (EIS), cyclability, scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). It is found that the LiFePO 4 battery with a composite LiPF 6-based electrolyte containing 1 wt% TMSB additive exhibits higher discharge retention and better cycling performance than the battery without TMSB additive at both 30 °C and 55 °C. SEM and XPS measurements show the changes of surface morphology and formation of solid electrolyte interface (SEI). EIS results indicate that the interfacial impedances of the batteries after cycled at 55 °C with the electrolyte containing TMSB additive are significantly smaller than the batteries without additive. The improved performances are ascribed to the enhancement of the thermal stability of the electrolyte and the modification of SEI component on the LiFePO 4 electrode.

The electronic effects in and the oxygen basicity of some oxygen-containing boranes

The oxygen relative basicity of di-n-butylboronous anhydride ((n-C4H9)2B)2O, ethyl di-n-butylboronite (n-C4H9)2BOC2H5 and some orthoborates (RO)3B having electrondonating and electronwithdrawing groups R was measured from the IR spectra of hydrogen bonds of phenol interacting with these compounds in CCl4 and analysed by means of the Taft equation. The substituent electronic effect of (n-C4H9)2B- and (RO)2B-groups attached to the oxygen of the-OR and -OB= moieties has been estimated asa more electronwithdrawing than that of structurally alike R2Z- and (RO)2Z-groups having Z = CH and SiCH3 and is discussed in terms of the vacant 2p orbital of the boron and a weak, if any, mutual polarizability effect of the alkoxy groups in orthoborates. The trimethylsiloxy group in trimethylsilyl borate possesses reduced electronwithdrawing ability compared to that in ((CH3)3SiO)3SiCH3 as a consequence of its great polarizability.