Correction: Tuning the morphology of sulfur-few layer graphene composites via liquid phase evaporation for battery application.

[This corrects the article DOI: 10.1039/D1NA00733E.].

Sustainable Synthesis of Sulfur-Single Walled Carbon Nanohorns Composite for Long Cycle Life Lithium-Sulfur Battery.

Lithium-sulfur batteries are considered one of the most appealing technologies for next-generation energy-storage devices. However, the main issues impeding market breakthrough are the insulating property of sulfur and the lithium-polysulfide shuttle effect, which cause premature cell failure. To face this challenge, we employed an easy and sustainable evaporation method enabling the encapsulation of elemental sulfur within carbon nanohorns as hosting material. This synthesis process resulted in a morphology capable of ameliorating the shuttle effect and improving the electrode conductivity. The electrochemical characterization of the sulfur-carbon nanohorns active material revealed a remarkable cycle life of 800 cycles with a stable capacity of 520 mA h/g for the first 400 cycles at C/4, while reaching a value around 300 mAh/g at the 750th cycle. These results suggest sulfur-carbon nanohorn active material as a potential candidate for next-generation battery technology.

Tuning the morphology of sulfur-few layer graphene composites via liquid phase evaporation for battery application.

A comparative study on sulfur-based composite electrodes comprising different few-layer graphene contents prepared via a facile evaporation method is presented here. The active material production process employed here, exploring different sulfur-few layer graphene ratios, enabled tuning and optimization of the sample morphology, as confirmed via a scanning electron microscopy study. The results reveal that the graphene content is a crucial parameter yielding an optimized morphology of spherical particles composed of an elemental sulfur inner core covered by the carbonaceous compound. The electrodes are characterized in lithium metal half-cells in terms of cyclic voltammetry, galvanostatic cycling tests, rate capability and electrochemical impedance spectroscopy. Moreover, the lithium-ion diffusion coefficients of each sample are obtained by the Randles-Sevcik equation in order to evaluate the reliability of the electrochemical processes. The lithium metal half-cell with the sulfur carbon composite active material exploiting a spherical particle morphology delivers a high specific capacity of 950 mA h g-1 after 100 cycles at C/4 with a coulombic efficiency of 98%. An optimized sample, tuned in terms of sulfur content and morphology, shows superior performance, exhibiting capacities of 1128 mA h g-1 and 842 mA h g-1 over 80 cycles at C/4 and 2C, respectively.

Inkjet Printing Infiltration of the Doped Ceria Interlayer in Commercial Anode-Supported SOFCs.

Single-step inkjet printing infiltration with doped ceria Ce0.9Ye0.1O1.95 (YDC) and cobalt oxide (CoxOy) precursor inks was performed in order to modify the properties of the doped ceria interlayer in commercial (50 × 50 × 0.5 mm3 size) anode-supported SOFCs. The penetration of the inks throughout the La0.8Sr0.2Co0.5Fe0.5O3-δ porous cathode to the Gd0.1Ce0.9O2 (GDC) interlayer was achieved by optimisation of the inks' rheology jetting parameters. The low-temperature calcination (750 °C) resulted in densification of the Gd-doped ceria porous interlayer as well as decoration of the cathode scaffold with nanoparticles (~20-50 nm in size). The I-V testing in pure hydrogen showed a maximum power density gain of ~20% at 700 °C and ~97% at 800 °C for the infiltrated cells. The latter effect was largely assigned to the improvement in the interfacial Ohmic resistance due to the densification of the interlayer. The EIS study of the polarisation losses of the reference and infiltrated cells revealed a reduction in the activation polarisations losses at 700 °C due to the nano-decoration of the La0.8Sr0.2Co0.5Fe0.5O3-δ scaffold surface. Such was not the case at 800 °C, where the drop in Ohmic losses was dominant. This work demonstrated that single-step inkjet printing infiltration, a non-disruptive, low-cost technique, can produce significant and scalable performance enhancements in commercial anode-supported SOFCs.

Towards enhanced sodium storage of anatase TiO2via a dual-modification approach of Mo doping combined with AlF3 coating.

Recent studies on anatase TiO2 have demonstrated its capability of performing as an anode material for sodium-ion batteries (SIBs) even though, due to poor conductivity, realistic applications have not yet been foreseen. In order to try to address this issue, herein, we shall introduce a cost effective and facile route based on the co-precipitation method for the synthesis of Mo-doped anatase TiO2 nanoparticles with AlF3 surface coating. The electrochemical measurements demonstrate that the Mo-doped anatase TiO2 nanoparticles deliver an ∼40% enhanced reversible capacity compared to pristine TiO2 (139.8 vs. 100.7 mA h g-1 at 0.1 C after 50 cycles) due to an improved electronic/ionic conductivity. Furthermore, upon AlF3 coating, the overall system can deliver a much higher reversible capacity of 178.9 mA h g-1 (∼80% increase with respect to pristine TiO2) with good cycling stability and excellent rate capabilities of up to 10 C. The experimental results indicate that the AlF3 surface coating could indeed effectively reduce the solid electrolyte interfacial resistance, enhance the electrochemical reactivity at the surface/interface region, and lower the polarization during cycling. The improved performance achieved using a cost-effective fabrication approach makes the dually modified anatase TiO2 a promising anode material for high-performance SIBs.

Inkjet Printing Functionalization of SOFC LSCF Cathodes.

An important segment of the future renewable energy economy is the implementation of novel energy generation systems. Such electrochemical systems are solid oxide fuel cells, which have the advantage of direct conversion of the chemical energy stored in the fuel to electrical energy with high efficiency. Improving the performance and lowering the cost of solid oxide fuel cells (SOFCs) are strongly dependent on finding commercially viable methods for nano-functionalization of their electrodes via infiltration. Inkjet printing technology was proven to be a feasible method providing scalability and high-resolution ink delivery. LaxSr1-xCoyFe1-yO3-δ cathodes were modified using inkjet printing for infiltration with two different materials: Gd-doped ceria (CGO) commonly used as ion-conductor and La0.6Sr0.4CoO3-δ (LCO) commonly used as a mixed ionic electronic conductor. As-modified surface structures promoted the extension of the three-phase boundary (TPB) and enhanced the mechanisms of the oxygen reduction reaction. Electrochemical impedance measurements revealed significantly lowered polarization resistances (between 2.7 and 3.7 times) and maximum power output enhancement of 24% for CGO infiltrated electrodes and 40% for LCO infiltrated electrodes.