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We investigated the effectiveness of using methylboronic acid MIDA ester (ADM) as an additive in an electrolyte to enhance the overall electrochemical and material properties of an LNCAO (LiNi0.8Co0.15Al0.05O2) cathode. The cyclic stability of the cathode material measured at 40 °C (@ 0.2 C) showed an enhanced capacity of 144.28 mAh g−1 (@ 100 cycles), a capacity retention of 80%, and a high coulombic efficiency (99.5%), in contrast to these same properties without the electrolyte additive (37.5 mAh g−1, ~ 20%, and 90.4%), thus confirming the effectiveness of the additive. A Fourier transform infrared spectroscopy (FTIR) analysis distinctly showed that the ADM additive suppressed the EC-Li+ ion coordination (1197 cm−1 and 728 cm−1) in the electrolyte, thereby improving the cyclic performance of the LNCAO cathode. The cathode after 100 charge/discharge cycles revealed that the ADM-containing system exhibited better surface stability of the grains in the LNCAO cathode, whereas distinct cracks were observed in the system without the ADM in the electrolyte. A transmission electron microscopy (TEM) analysis revealed the presence of a thin, uniform and dense cathode electrolyte interface (CEI) film on the surface of LNCAO cathode. An operando synchrotron X-ray diffraction (XRD) test identified the high structural reversibility of the LNCAO cathode with a CEI layer formed by the ADM, which effectively maintained the structural stability of the layered material. The additive effectively inhibited the decomposition of electrolyte compositions, as confirmed by X-ray photoelectron spectroscopy (XPS). [ABSTRACT FROM AUTHOR]

Mechanochemical synthesis of Si/Cu3Si-based composite as negative electrode materials for lithium ion battery is investigated. Results indicate that CuO is decomposed and alloyed with Si forming amorphous Cu-Si solid solution due to high energy impacting during high energy mechanical milling (HEMM). Upon carbonization at 800 °C, heating energy induces Cu3Si to crystallize in nanocrystalline/amorphous Si-rich matrix enhancing composite rigidity and conductivity. In addition, residual carbon formed on outside surface of composite powder as a buff space further alleviates volume change upon lithiation/delithiation. Thus, coin cell made of C-coated Si/Cu3Si-based composite as negative electrode (active materials loading, 2.3 mg cm−2) conducted at 100 mA g−1 performs the initial charge capacity of 1812 mAh g−1 (4.08 mAh cm−2) columbic efficiency of 83.7% and retained charge capacity of 1470 mAh g−1 (3.31 mAh cm−2) at the end of the 100th cycle, opening a promised window as negative electrode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]