RESUMEN
NASICON type KTi2(PO4)3 decorated by NTCDA-derived carbon layer (KTP/NC) was prepared as anode material to obtain sustainable lithium/sodium ion storage (LIBs/SIBs). Due to its prominent capacitance, good electronic conductivity and ability to constrain volume, the KTP/NC composite realizes highly electrochemical kinetics both in LIBs and SIBs. For LIBs, the KTP/NC composite delivers a superior reversible capacity of 598.1 mAh g-1 after 200 cycles at 0.5C, impressive cyclability with 225.5 mAh g-1 after 3000 cycles at an ultrahigh current density of 26.1 C and conspicuous rate performance of 160.6 mAh g-1 even at 52.2 C. In addition, the composite has a wide operation-temperature window with favorable capacities of 147.1-372.9 mAh g-1 from -10 °C to 50 °C. As for SIBs, the KTP/NC composite maintains a stable discharge capacity of 112.5 mAh g-1 after 700 cycles at a current density of 2.6 C and conspicuous rate performance of 86.7 mAh g-1 at 5.2 C. The KTP/NC anode exhibits discharge capacities of 29.9-112.6 mAh g-1 from -10 °C to 40 °C. The results demonstrate that the KTP/NC composite would be a promising electrode material for LIBs and SIBs.
RESUMEN
The dissolution of LiNO3 in carbonate electrolytes is achieved by introducing pyridine as a new carrier solvent owing to its higher Gutmann donor number than NO3-. The Li metal anode in LiNO3-containing carbonate electrolyte demonstrates a much enhanced reversibility due to the preferential reduction of LiNO3 and the formation of an inorganic-rich SEI.
RESUMEN
In this work, a novel high-voltage electrolyte additive, tetraethylthiophene-2,5-diylbismethylphosphonate (TTD), was synthesized, and the influence of TTD on the electrolyte and its electrochemical performance under different voltages were studied by changing the content of the TTD additive. The results showed that the TTD additive significantly improved the capacity, cycle stability, and rate capability of batteries when charging/discharging at high voltages. After adding 1 % TTD to the basic electrolyte, the capacity retention rate of batteries after 200 cycles at 4.2, 4.3, 4.4, and 4.5â V increased by 20.8, 18.3, 50, and 31.9 %, respectively. In addition, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) results showed that TTD could effectively inhibit the decomposition of the electrolyte and participate in the formation of a uniform, thin, and stable cathode electrolyte interphase (CEI) film on the electrode surface, thereby effectively inhibiting the side reaction between the electrolyte decomposition product and the CEI membrane, and finally improving the high-voltage performance of the battery. The TTD additive may provide a cost-effective solution for high-performance high-voltage electrolytes.