Graphite-anchored lithium vanadium oxide as anode of lithium ion battery

Graphite-anchored lithium vanadium oxide (Li1.1V0.9O2) has been synthesized via a “one-pot” in situ method. The effects of the synthesis conditions, such as the ratio of reaction components and calcination temperature, on the electrochemical performance are systematically investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), galvanostatic discharge/charge tests and differential scanning calorimetry (DSC). Compared with the simple mixture of graphite and lithium vanadium oxide, the graphite-anchored lithium vanadium oxide delivers an enhanced reversible capacity, rate capability and cyclic stability. It also shows better thermal stability.Web of Scienc

The Interface between Li6.5La3Zr1.5Ta0.5O12 and Liquid Electrolyte

An advantageous solid electrolyte/liquid electrolyte interface is crucial for the implementation of a protected lithium anode in liquid electrolyte cells. Li6.5La3Zr1.5Ta0.5O12 (LLZTO) garnet electrolytes are among the few solid electrolytes that are stable in contact with lithium metal. We show LLZTO is unstable in contact with the organic carbonate-based Li+ liquid electrolyte used in conventional Li-ion cells. The interfacial resistance between LLZTO and LiPF6 in (CH2O)2CO: OC(OCH3)2 (1:1 v/v) increases with time due to the growth of a lithium-ion-conducting solid electrolyte interphase (SEI) at the surface of the ceramic electrolyte. The interphase is composed of Li2CO3, LiF, Li2O, and organic carbonates. Even at a rate of 5 mA cm−2, a 3 V potential drop occurs across the LLZTO/liquid electrolyte interface. A practical LLZTO membrane (thickness ∼10 μm), in contact with a lithium anode, gives a potential loss of ∼16 mV, less than 1% of the resistance of the SEI

Progress, challenges and perspectives of computational studies on glassy superionic conductors for solid-state batteries

Sulfide-based glasses and glass-ceramics showing high ionic conductivities and excellent mechanical properties are considered as promising solid-state electrolytes. Nowadays, the computational material techniques with the advantage of low research cost are being widely utilized for understanding, effectively screening and discovering of battery materials. In consideration of the rising importance and contributions of computational studying on the glassy SSE materials, here, this work summarizes the common computational methods utilized for studying the amorphous inorganic materials, review the recent progress in computational investigations of the lithium and sodium sulfide-type glasses for solid-state batteries, and outlines our understandings of the challenges and future perspective on them. This review would facilitate and accelerate the future computational screening and discovering more glassy-state SSE materials for the solid-state batteries

Suppressing the Phase Transition of the Layered Ni-Rich Oxide Cathode during High-Voltage Cycling by Introducing Low-Content Li₂MnO₃

The layered Ni-rich oxide cathode (LiNi_0.8Co_0.1Mn_0.1O₂) suffers from a tremendous structural degradation during high-voltage cycling (4.8 V), causing the drastic rise of electrode impedance and deterioration of the capacity retention. Here, we develop an effective strategy to overcome these problems of the Ni-rich cathode material through doping low-content Li₂MnO₃ as an excellent structure stabilizer. Cyclic voltammogram and ex-situ X-ray diffraction measurements have reveled that Li₂MnO₃ could display a remarkable suppression effect on the phase transition of LiNi_0.8Co_0.1Mn_0.1O₂. The electrochemical tests showed that Li₂MnO₃-stabilized LiNi_0.8Co_0.1Mn_0.1O₂ could realize the large reversible capacity, stable discharge voltage and excellent cycling life during high-voltage cycling, which could be benefited from the enhanced structural stability of the modified Ni-rich cathode. The Li₂MnO₃ could sufficiently suppress the phase transition between two hexagonal phase (H2 and H3) with distinctly different lattice parameters, significantly reducing variation of unit-cell volume, which facilitates stabilization of the original layered structure of LiNi_0.8Co_0.1Mn_0.1O₂ cathode during high-voltage cycling