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Hybrid silica-based nanofillers were synthesised by grafting short chains of poly(ethylene glycol) (PEG) with different molecular weight on the surface of SiO2 porous nanoparticles. Based on this approach, homogeneous poly(ethylene oxide) (PEO)-based ceramic-in-polymer solid-state electrolytes with SiO2 loadings up to 23 wt% were obtained, thanks to the high compatibility between the two phases endowed by the grafted PEG chains. These electrolytes showed satisfying ionic conductivity and excellent resistance against dendrite piercing that enabled long operation, for more than 350 h, under continuous stripping/plating of lithium in symmetric Li/electrolyte/Li cells. Additionally, the operating life of these devices was improved by the self-healing reaction between Li dendrites and silica fillers, being able to reinstate the cycling after short circuit. Finally, a lithium metal full cell, equipped with LiFePO4 positive material and the solid-state electrolyte containing 18 wt% of SiO2, demonstrated high stability against dendrite penetration and discharge capacity at 70 °C comparable to cells based on liquid analogues.

In the last decade, dealloying has become a popular and effective strategy to fabricate nanoporous metals used in electrochemical applications such as electrocatalysis and energy storage. This review article summarizes the recent literature on dealloyed non-noble metals and oxides evaluated as lithium-ion battery anode materials. The importance of dealloying parameters to achieve desired pore and ligament sizes is emphasized. A future research roadmap is also provided.

In the last decade, dealloying has become a popular and effective strategy to fabricate nanoporous metals used in electrochemical applications such as electrocatalysis and energy storage. This review article summarizes the recent literature on dealloyed non-noble metals and oxides evaluated as lithium-ion battery anode materials. The importance of dealloying parameters to achieve desired pore and ligament sizes is emphasized. A future research roadmap is also provided.

The demand for batteries that can meet the high energy density and reliability needs of the future is ever growing and drives current research trends in the battery field toward the development of practical metallic Li anodes. Overcoming the difficult rechargeability and safety obstacles that affected the first-generation lithium-ion batteries in decades past has required diligent research and introduced of a host of new material systems, including solid-state inorganic electrolytes. Solid-state electrolytes represent a fundamental departure from conventional liquid-electrolyte lithium-ion batteries and offer a path toward versatile and high-energy-density energy storage. Inorganic solid-state electrolytes have still faced challenges, such as unfavorable interface characteristics with electrode materials and low ionic conductivity compared to liquid electrolytes, but recent advancements have helped to overcome these obstacles and position solid-state electrolytes as promising candidates for use in state-of-the-art batteries. To achieve widespread adoption of solid-state electrolytes, however, prevailing issues like Li dendrite formation and subsequent electrical shorting must be understood and solved. Based on research that suggests a dependence of dendrite formation on the electronic conductivity of garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZO-Ta) solid electrolyte, I first investigate a thin, conformal layer of electronic-insulating, ion-conducting lithium phosphorus oxynitride (LiPON) deposited at the interface between garnet-type electrolyte and a metallic Li alloy anode. Using atomic layer deposition to ensure continuity of the LiPON layer across the garnet LLZO-Ta surface, I fabricate Li-Li symmetric cells that achieve long cycle life free of dendrites. After demonstrating the merits of a thin, electronically insulating layer applied at the interface between Li metal and LLZO-Ta, I probe into the relationship between the ionic and electronic conductivity of soli

LiNO3 has been widely used as an effective electrolyte additive in lithium-sulfur (Li-S) batteries to suppress the polysulfide shuttle effect. To better understand the mechanism of suppressed shuttle effect by LiNO3, herein we report a comprehensive investigation of the influence of LiNO3 additive on the formation process of the solid electrolyte interphase (SEI) layer on lithium anode of Li-S batteries by operando X-ray absorption spectroscopy (XAS). We observed that a compact and stable SEI layer composed of Li2SO3 and Li2SO4 on top of lithium anode is formed during the initial discharge process due to the synergetic effect of shuttled polysulfides and LiNO3, which can effectively suppress the subsequent reaction between polysulfides in electrolyte and lithium metal and thus result in the alleviation of polysulfide shuttle effect. In contrast, when using electrolyte without LiNO3, the shuttled polysulfides continuously react with lithium metal to form insulating Li2S on lithium anode, leading to the irreversible capacity loss. Our present operando XAS study provides a valuable insight into the important role of LiNO3 for the protection of lithium anodes, which will be beneficial for the further development of new electrolyte additives for high-performance Li-S batteries.

LiNO3 has been widely used as an effective electrolyte additive in lithium-sulfur (Li-S) batteries to suppress the polysulfide shuttle effect. To better understand the mechanism of suppressed shuttle effect by LiNO3, herein we report a comprehensive investigation of the influence of LiNO3 additive on the formation process of the solid electrolyte interphase (SEI) layer on lithium anode of Li-S batteries by operando X-ray absorption spectroscopy (XAS). We observed that a compact and stable SEI layer composed of Li2SO3 and Li2SO4 on top of lithium anode is formed during the initial discharge process due to the synergetic effect of shuttled polysulfides and LiNO3, which can effectively suppress the subsequent reaction between polysulfides in electrolyte and lithium metal and thus result in the alleviation of polysulfide shuttle effect. In contrast, when using electrolyte without LiNO3, the shuttled polysulfides continuously react with lithium metal to form insulating Li2S on lithium anode, leading to the irreversible capacity loss. Our present operando XAS study provides a valuable insight into the important role of LiNO3 for the protection of lithium anodes, which will be beneficial for the further development of new electrolyte additives for high-performance Li-S batteries.

The SEI layer formed on metallic Li which has been used as an anode in a Li-O2 battery is studied for the first time. We have used XPS to monitor the surface composition of the lithium electrode and have identified the various chemical species present. The XPS results indicated that the composition of the SEI layer is affected by the presence of oxygen and is unstable during cycling. We also observed decomposition products from the binder material used in the cathode on the surface of the lithium anode. This new SEI layer has an increased resistance affecting the lithium deposition which is essential for battery operation.

The surface compositions of a MnO2 catalyst containing carbon cathode and a Li anode in a Li–O2 battery were investigated using synchrotron-based photoelectron spectroscopy (PES). Electrolytes comprising LiClO4 or LiBOB salts in PC or EC:DEC (1:1) solvents were used for this study. Decomposition products from LiClO4 or LiBOB were observed on the cathode surface when using PC. However, no degradation of LiClO4 was detected when using EC/DEC. We have demonstrated that both PC and EC/DEC solvents decompose during the cell cycling to form carbonate and ether containing compounds on the surface of the carbon cathode. However, EC/DEC decomposed to a lesser degree compared to PC. PES revealed that a surface layer with a thickness of at least 1–2 nm remained on the MnO2 catalyst at the end of the charged state. It was shown that the detachment of Kynar binder influences the surface composition of both the carbon cathode and the Li anode of Li–O2 cells. The PES results indicated that in the charged state the SEI on the Li anode is composed of PEO, carboxylates, carbonates, and LiClO4 salt.

The effect of the carbon precursors morphology during a mechanical grinding experiment on the physical/electrochemical properties of the resulting ball-milled carbonaceous powders was studied. These properties strongly depend on the type of grinding mode used (shear or shock-type grinding); however, for each grinding mode, they were found to be totally independent of the nature of the precursor used (graphite, carbon, coke) and/or of its morphology (layers, microbeads and fibres). Eighty h of shock-grinding was found to produce carbonaceous milled powders able to reversibly intercalate two lithiums per six carbons 'Li2C6' while still having an irreversible capacity of 0.8 Li. The transparency of the precursor morphology and nature to mechanical grinding with carbon materials is ascribed to the strong 2D character of the graphite structure. Finally, the observed large reversible capacity in our hydrogen-free carbonaceous milled samples is explained on the basis of the previously proposed 'house of cards' model.

The effect of the carbon precursors morphology during a mechanical grinding experiment on the physical/electrochemical properties of the resulting ball-milled carbonaceous powders was studied. These properties strongly depend on the type of grinding mode used (shear or shock-type grinding); however, for each grinding mode, they were found to be totally independent of the nature of the precursor used (graphite, carbon, coke) and/or of its morphology (layers, microbeads and fibres). Eighty h of shock-grinding was found to produce carbonaceous milled powders able to reversibly intercalate two lithiums per six carbons 'Li2C6' while still having an irreversible capacity of 0.8 Li. The transparency of the precursor morphology and nature to mechanical grinding with carbon materials is ascribed to the strong 2D character of the graphite structure. Finally, the observed large reversible capacity in our hydrogen-free carbonaceous milled samples is explained on the basis of the previously proposed 'house of cards' model.