Direct observation of lithium metal dendrites with ceramic solid electrolyte

Dendrite formation, which could cause a battery short circuit, occurs in batteries that contain lithium metal anodes. In order to suppress dendrite growth, the use of electrolytes with a high shear modulus is suggested as an ionic conductive separator in batteries. One promising candidate for this application is Li7La3Zr2O12 (LLZO) because it has excellent mechanical properties and chemical stability. In this work, in situ scanning electron microscopy (SEM) technique was employed to monitor the interface behavior between lithium metal and LLZO electrolyte during cycling with pressure. Using the obtained SEM images, videos were created that show the inhomogeneous dissolution and deposition of lithium, which induce dendrite growth. The energy dispersive spectroscopy analyses of dendrites indicate the presence of Li, C, and O elements. Moreover, the cross-section mapping comparison of the LLZO shows the inhomogeneous distribution of La, Zr, and C after cycling that was caused by lithium loss near the Li electrode and possible side reactions. This work demonstrates the morphological and chemical evolution that occurs during cycling in a symmetrical Li–Li cell that contains LLZO. Although the superior mechanical properties of LLZO make it an excellent electrolyte candidate for batteries, the further improvement of the electrochemical stabilization of the garnet–lithium metal interface is suggested

Understanding the Reactivity of a Thin Li1.5Al0.5Ge1.5(PO4)3 Solid-State Electrolyte toward Metallic Lithium Anode

The thickness of solid-state electrolytes (SSEs) significantly affects the energy density and safety performance of all-solid-state lithium batteries. However, a sufficient understanding of the reactivity toward lithium metal of ultrathin SSEs (<100 µm) based on NASICON remains lacking. Herein, for the first time, a self-standing and ultrathin (70 µm) NASICON-type Li1.5Al0.5Ge1.5(PO4)3 (LAGP) electrolyte via a scalable solution process is developed, and X-ray photoelectron spectroscopy reveals that changes in LAGP at the metastable Li–LAGP interface during battery operation is temperature dependent. Severe germanium reduction and decrease in LAGP particle size are detected at the Li–LAGP interface at elevated temperature. Oriented plating of lithium metal on its preferred (110) face occurs during in situ X-ray diffraction cycling

Exploring the Ni redox activity in polyanionic compounds as conceivable high potential cathodes for Na rechargeable batteries

Although nickel-based polyanionic compounds are expected to exhibit a high operating voltage for batteries based on the Ni2+/3+ redox couple activity, some rare experimental studies on the electrochemical performance of these materials are reported, resulting from the poor kinetics of the bulk materials in both Li and Na nonaqueous systems. Herein, the electrochemical activity of the Ni2+/3+ redox couple in the mixed-polyanionic framework Na4Ni3(PO4)2(P2O7) is reported for the first time. This novel material exhibits a remarkably high operating voltage when cycled in sodium cells in both carbonate- and ionic liquid-based electrolytes. The application of a carbon coating and the use of an ionic liquid-based electrolyte enable the reversible sodium ion (de-)insertion in the host structure accompanied by the redox activity of Ni2+/3+ at operating voltages as high as 4.8 V vs Na/Na+. These results present the realization of Ni-based mixed polyanionic compounds with improved electrochemical activity and pave the way for the discovery of new Na-based high potential cathode materials

LiFePO4 Surface Reactivity

International audienc

Immobilization of complexes of some heavy metals with a 2-(4-pyridylazo)-resorcinol “PAR” on Algerian hydrothermal clay

International audienc

Effect of conductive additives in LiFePO4 cathode for lithium-ion batteries

The electrochemical properties of LiFePO4 cathodes with different carbon contents were studied to find out the role of carbon as conductive additive. LiFePO4 cathodes containing from 0 percent to 12 percent of conductive additive (carbon black or mixture of carbon black and graphite) were cycled at different C rates. The capacity of LiFePO4 cathode increased, as conductive additive content increased. Carbon increased the utilization of active material and the electrical conductivity of electrode, but decreased volumetric capacity of electrode

Review-Li-Ion Photo-Batteries: Challenges and Opportunities

Humanity's greatest challenge in the 21st century consists in transitioning from fossil fuels towards renewable energy technologies. Since all renewable are intermittent, the common challenge for all renewables is storage. In this context, designing and realizing hybrid devices that combine energy conversion with storage represents a major opportunity. Among renewables, solar energy is particularly important, because in one hour the Sun sends towards us enough energy to power the whole planet for one year; nevertheless, our current global use of solar energy is only about 1%, The aim of this short review is to describe the current state of the art and perspectives in the emerging area of photo-rechargeable batteries. This hybrid device consists in a photo-electrochemical system that combines solar energy conversion with electrochemical storage, storing energy during the day and allowing release at night. While the opportunity of combining solar and battery technologies into a single system is promising, major challenges are yet to be overcome. Here we summarize the most promising architectures developed so far and potential research directions in this exciting area of technology

LiFePO{sub 4}/gel/natural graphite cells for the BATT program

LiFePO{sub 4}/gel/natural graphite (NG) cells have been prepared and cycled under a fixed protocol for cycle and calendar life determination. Cell compression of 10 psi was found to represent an optimal balance between cell impedance and the first cycle losses on the individual electrodes with the gel electrolyte. Cells with a Li anode showed capacities of 160 and 78 mAh/g-LiFePO{sub 4} for C/25 and 2C discharge rates, respectively. Rapid capacity and power fade were observed in the LiFePO{sub 4}/gel/NG cells during cycling and calendar life studies. Diagnostic evaluations point to the consumption of cycleable Li though a side reaction as the reason for performance fade with minimal degradation of the individual electrodes

Novel Li-ion polymer batteries using LiFePO4 as positive electrode

983-988The aging and performance of natural graphite/PEO-based gel electrolyte/ LiFePO4 cells have been reported. The gel polymer electrolytes have been produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite anode in gel electrolyte containing LiBF4 -EC/GBL exhibits high reversible capacity (345mAh/g) and high coulombic efficiency (91%). The LiFePO4 cathode in the same gel-polymer exhibits a reversible capacity of 150 mAh/g and 83% coulombic efficiency. Better performance has been obtained at high-rate discharge with 6% carbon additive in the cathode. However, the graphite anode performance suffers at high rate. The Li-ion gel polymer battery shows a capacity fade of 13% after 180 cycles and has poor performance at low temperature. Li/polymer/LiFePO4 has an excellent stable cycle life