The relationship between the structure of bis (2,4,4-trimethylpentyl) phosphinic acid (BTPA), diethyl phosphinic acid (DEPA), and diphenyl phosphinic acid (DPPA) on the flotation performance of malachite was investigated. Through a series of flotation experiments, density functional theory (DFT) calculations, and surface analysis methods, we aimed to deeply understand the microscopic mechanism of the interactions between these collectors and the malachite surface. The experimental results showed that BTPA exhibited excellent selectivity and flotation performance for malachite in the pH range of 5.0–11.0, significantly better than DEPA and DPPA. Surface analysis evidence from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) further confirmed the chemical adsorption characteristics of BTPA on the malachite surface. DFT calculations revealed that the adsorption capacity of BTPA on the malachite surface exceeds that of DEPA and DPPA. Electron transfer analysis, especially through frontier molecular orbital theory, differential charge density, PDOS, and COHP analysis, indicated that the charge transfer process from the s orbitals of oxygen atoms in the collectors to the d orbitals of copper atoms on the mineral surface is the decisive factor for the adsorption strength.
Liqin Xiong,Zheng Cheng,Guorong Hu,Yanbing Cao,Zhongdong Peng,Bin Zhang,Ke Du
High-voltage spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) emerges as an ideal cathode for high energy density lithium-ion batteries due to its 4.7 V operating voltage and low-cost manganese-rich composition. However, the severe interfacial degradation caused by transition metal dissolution and pervasive electrolyte decomposition compromises practical viability in commercial lithium-ion batteries, critically under elevated-temperature operation. To address this problem, we constructed a covalently anchored bis[3-(trimethoxysilyl)propyl]amine (BTPA) coating layer on the LNMO surface through atomic-scale grafting. The BTPA-coated LNMO confers exceptional cyclic stability and rate capability, representing a transformative advancement in cathode performance. At 50 °C, BTPA-coated LNMO cathode maintains 96.10 % capacity retention after 100 cycles at 1C, significantly outperforming pristine LNMO (58.92 % retention), while demonstrating exceptional rate capability with 109.42 mAh·g −1 delivered at 10C compared to 92.71 mAh·g −1 for the pristine LNMO. The synergistic suppression of Mn 3+ formation and parasitic reactions underpins unprecedented high-temperature cyclability, establishing a paradigm for extreme-condition energy storage.
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