Facile Fabrication of Ethoxy-Functional Polysiloxane Wrapped LiNi0.6Co0.2Mn0.2O2 Cathode with Improved Cycling Performance for Rechargeable Li-Ion Battery.

Dealing with the water molecule on the surface of LiNi0.6Co0.2Mn0.2O2 (NCM) cathode and hydrogen fluoride in the electrolyte is one of the most difficult challenges in Li-ion battery research. In this paper, the surface polymerization of tetraethyl orthosilicate (TEOS) on NCM to generate ethoxy-functional polysiloxane (EPS) wrapped NCM (E-NCM) cathode under mild conditions and without any additions is utilized to solve this intractable problem. The differential scanning calorimetry, transmission electron microscopy, and X-ray photoelectron spectroscopy results show that the formed amorphous coating can provide a protective shell to improve the NCM thermal stability, suppress the thickening of the solid electrolyte interphase (SEI) layer, and scavenge HF in the electrolyte. The E-NCM composite with 2 mol % EPS delivers a high discharge capacity retention of 84.9% after 100 cycles at a 1 C discharge rate in the 2.8-4.3 V potential range at 55 °C. Moreover, electrochemical impedance spectroscopy measurements reveal that the EPS coating could alleviate the impedance rise during cycling especially at an elevated temperature. Therefore, the fabricated E-NCM cathode with long-term cycling and thermal stability is a promising candidate for use in a high-energy Li-ion battery.

Fabrication of high optical transparent and conductive SWNT based transparent conducting film on flexible plastic substrate using ozone as a redox dopant.

In the present work, single-wall carbon nanotubes-transparent conducting films (SWNTs-TCFs) were fabricated at room temperature on a flexible polycarbonate substrate using the ultrosonication-dip-coating technique. Ozone was employed to reduce the sheet resistance of conductive film. As a result, the sheet resistance of film was decreased drastically after 1.5 hr ozone (O3) treatment and could reach up to 170 omega/square at 80% T at 550 nm wavelength. In addition, aminopropyltriethoxysilane (APTS) was further applied as an adhesion promoter in order to enhance the adhesion between the SWNTs films and the substrate. Experimental results show that ATPS can greatly improve the adhesion of SWNTs coating to the substrate without the loss of conductivity.