Nano-phase tin hollandites, K2(M2Sn6)O16(M = Co, In) as anodes for Li-ion batteries

摘要: The nano-phase tin hollandites, K2(M2Sn6)O16 (M = Co, In) of particle size <10 nm are prepared by high energy ball-milling pre-synthesized compounds and characterized X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission (HR-TEM) selected area (SAED) techniques. Li-cycling behavior M Co (nano-(K–Co)) In (nano-(K–In)) is evaluated galvanostatic cycling cyclic voltammetry (CV) with Li-metal as counter electrode in the voltage range, 0.005–0.8 V (or 1.0 V). When cycled at 60 mA g−1 (0.12 C) V, a stable capacity 500 (±5) h up to cycles noticed for nano-(K–Co), whereas nano-(K–In) showed an initial 570 g−1, which dropped 485 (15% loss) end cycles. At 1 C-rate, nano-(K–Co) 410 least 100 Under similar conditions, heat-treated (300 °C, 12 h, Ar) significant improvement gave range 5–50 Coulombic efficiencies both increased 96–98% 10–60 For nano-phases, average discharge potential 0.13 charge 0.5 vs.Li, determined CV data. Electrochemical impedance spectroscopy (EIS) data on function presented discussed. apparent Li-diffusion co-efficient (DLi+), estimated from EIS data, 2.0–2.6 (±0.2) × 10−14 cm2s−1 between 0.25 0.45 during first-cycle. observed have been interpreted terms alloying–de-alloying reaction Sn nano-composite, ‘Sn–K2O–Co/In–Li2O’.