Guided dendrite-free lithium deposition through titanium nitride additive in Li metal batteries

Metallic lithium (Li) is one of the most potential anode materials in the near future, because of its high theoretical specific capacity (3865 mAh/g), low potential (−3.045 V vs standard hydrogen electrode (SHE)) and low density (0.534 g/cm³). However, fatal dendritic Li growth is the bottleneck of the development of Li anode. In this contribution, we reported a titanium nitride (TiN) nanoparticle additive to guide Li deposition uniformly, hence dead Li and dendritic Li are effectively reduced. There are more nucleation sites on the surface of the electrode due to the stronger adsorption of Li ions on each facet of TiN, and TiN nanoparticles play the role of seeds of Li deposition. The half cells cycling in additive electrolyte exhibit an average Coulombic efficiency (CE) of 97.19% for 270 cycles on plane copper (Cu) electrode and an excellent high average CE of 99.01% for 300 cycles on three-dimensional (3D) carbon paper (CP) electrode at 1 mA/cm² and 1 mAh/cm². Li–S full cells equipped with such TiN nanoparticles additive electrolyte deliver great enhanced cycling and rate performance. This work provides a new insight to suppress Li dendrite and realizing high performance of Li metal batteries.     

A novel titania nanorods‐filled composite solid electrolyte with improved room temperature performance for solid‐state Li‐ion battery

Solid‐state batteries (SSBs) with room temperature (RT) performances had been one of the most promising technologies for energy storage. To achieve a chemical stable and high ionic conductive solid electrolyte, herein, a titania (TiO₂) (B) nanorods‐filled poly(propylene carbonate) (PPC)‐based organic/inorganic composite solid electrolyte (CSE) was prepared for the first time. It was found that by using TiO₂(B) nanorods, the ionic conductivity of the CSE membrane could be improved to 1.52 × 10^?4 S/cm, the electrochemical stable window was more than 4.6 V, and the tensile strength reaches 27 MPa with a strain less than 6%. The CSE was applied for SSB and showed excellent room temperature electrochemical performances. At 25°C, the LiFePO₄/CSE/Li SSB with 3%TiO₂‐filled CSE had the first cycle specific discharge capacity of 162 mAh/g with a capacity retention of 93% after 100 cycles at 0.3C. While the NCM622/CSE/Li SSB with 3%TiO₂‐filled CSE had the first specific discharge capacity of 165 mAh/g with a capacity retention of 88% after 100 cycles at 0.3C. The enhancement effect of TiO₂(B) nanorods could be ascribed that the rod‐like fillers provide more continuous Li‐ion transport path compared with nano particles, and the surface porosity and composition of TiO₂(B) nanorods could also improve the interfacial contact and Lewis acid‐base reaction sites between polymer and fillers. The TiO₂(B) nanorods‐filled CSE with high chemical stability, potential window, and ionic conductivity was promising to meet the requirements of SSBs.     

TiO2 nanotubes supported ultrafine MnCo2O4 nanoparticles as a superior-performance anode for lithium-ion capacitors

Lithium-ion capacitors (LICs) are considered as a promising energy storage device possessing large specific energy along with high specific power due to the integration of the merits of electric double-layer capacitors (ELDCs) and lithium-ion batteries (LIBs). In the present work, TiO₂ nanotubes supported ultrafine MnCo₂O₄ nanoparticles with the size of 5–10 nm is solvothermally synthesized. It is found that the introduction of TiO₂ nanotubes can weaken the aggregation of MnCo₂O₄ nanoparticles, therefore causing the enhancement in the electrode/electrolyte interfacial contact and the reduction in Li ⁺ diffusion path. Benefiting from the synergy effect of MnCo₂O₄ and TiO₂ which can alleviate the volume change of MnCo₂O₄, the MnCo₂O₄/TiO₂ composite used in LIBs displays a large reversible capacity of 743 mAh g⁻¹ at 0.2 A g⁻¹ after 100 cycles and impressive rate performance. This composite as anode is assembled with an activated carbon (AC) electrode as cathode into MnCo₂O₄/TiO₂//AC LIC working in a wide voltage range of 0.5–4 V. This LIC can deliver high specific energies of 89.8 and 44.1 Wh kg⁻¹ at specific power of 0.25 and 3.41 kW kg⁻¹, respectively, and presents outstanding cyclic stability (76.4% of initial capacity at the end of 5000 cycles).     

Insight into effects of graphene and zinc oxide in Li4Ti5O12 as anode materials for Li-ion full-cell battery

Programmable design of nanocomposites of Li₄Ti₅O₁₂ (LTO) conducted through hydrothermal route in the presence of ethylenediamine as basic and capping agent. In this work, effect of ZnO and Graphene on the Li₄Ti₅O₁₂ based nanocomposites as anode materials investigated for Li-Ion battery performances. The full cells battery assembled with LTO based nanocomposites on Cu foil as the anode electrode and commercial LMO (LiMn₂O₄) on aluminum foil as cathode electrode. X-Ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), along with Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission electron microscopy (TEM) images was applied for study the composition and structure of as-prepared samples. The electrochemical lithium storage capacity of prepared nanocomposites was compared with pristine LTO via chronopotentiometry charge-discharge techniques at 1.5–4.0 V and current rate of 100 mA/g. As a result, the electrode which is provided by LTO/TiO₂/ZnO and LTO/TiO₂/graphene nanocomposites provided 765 and 670 mAh/g discharge capacity compared with pristine LTO/TiO₂ (550 mAh/g) after 15 cycles. Based on the obtained results, fabricated nanocomposites can be promising compounds to improve the electrochemical performance of lithium storage.     

Tuning of electrocatalytic activity of WO3–TiO2 nanocomposite electrode for alkaline hydrogen evolution reaction

The study reports the synthesis of mesoporous WO₃–TiO₂ nanocomposite with tuned particle size (~7 nm), pore diameter (~4.9 nm), specific surface area (S_BET = 129.112 m²/g) and pore volume (V_tot = 0.185 cm³/g) by an acid catalyzed peptization method, and its utilization for the development of stable catalytic electrode with enhanced activity towards alkaline hydrogen evolution reaction (HER). The SEM and AFM analyses confirm the formation of good quality composite electrodes with improved surface roughness through electroless deposition method. The developed WO₃–TiO₂ nanocomposite electrode exhibits low overpotential value of 120 mV with an exchange current density of 6.20 × 10^?5 mA/cm², and a low Tafel slope value of 98 mV/dec. Apart from the high HER performance, the developed WO₃–TiO₂ nanocomposite electrode exhibits competency with the state-of-the-art electrode materials for alkaline HER in industrial processes with sustained catalytic activity, tolerance behavior and long-term stability.     

Energy storage of thermally reduced graphene oxide

The energy-storage capacity of reduced graphene oxide (rGO) is investigated in this study. The rGO used here was prepared by thermal annealing under a nitrogen atmosphere at various temperatures (300, 400, 500 and 600 °C). We measured high-pressure H₂ isotherms at 77 K and the electrochemical performance of four rGO samples as anode materials in Li-ion batteries (LIBs). A maximum H₂ storage capacity of ∼5.0 wt% and a reversible charge/discharge capacity of 1220 mAh/g at a current density of 30 mA/g were achieved with rGO annealed at 400 °C with a pore size of approximately 6.7 Å. Thus, an optimal pore size exists for hydrogen and lithium storage, which is similar to the optimum interlayer distance (6.5 Å) of graphene oxide for hydrogen storage applications.     

Improving hydrogen production via water splitting over Pt/TiO2/activated carbon nanocomposite

Mesoporous TiO₂/AC, Pt/TiO₂ and Pt/TiO₂/AC (AC = activated carbon) nanocomposites were synthesized by functionalizing the activated carbon using acid treatment and sol–gel method. Photochemical deposition method was used for Pt loading. The nano-photocatalysts were characterized using XRD, SEM, DRS, BET, FTIR, XPS, CHN and ICP methods. The hydrogen production, under UV light irradiation in an aqueous suspension containing methanol has been studied. The effect of Pt, methanol and activated carbon were investigated. The results show that the activated carbon and Pt together improve the hydrogen production via water splitting. Also methanol acts as a good hole scavenger. Mesoporous Pt/TiO₂/AC nanocomposite is the most efficient photocatalyst for hydrogen production compared to TiO₂/AC, Pt/TiO₂ and the commercial photocatalyst P25 under the same photoreaction conditions. Using Pt/TiO₂/AC, the rate of hydrogen production is 7490 μmol (h g catal.)⁻¹ that is about 75 times higher than that of the P25 photocatalyst.     

Facile synthesis and electrochemical hydrogen storage of bentonite/TiO2/Au nanocomposite

In this study, the electrochemical hydrogen storage of bentonite composites containing TiO₂ and Au nanoparticles (NPs) has been investigated by cyclic voltammetry (CV) analysis. TiO₂ NPs were first deposited on the bentonite substrate by reflux technique. Au NPs were then prepared by laser ablation in liquid (LAL) method under different laser irradiation times (6, 12, and 18 min), and utilized in the decoration of bentonite/TiO₂ nanocomposite by physical mixing. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and elemental mapping were carried out in the characterization of the prepared bentonite/TiO₂/Au nanocomposite. The surface and chemical properties of the acquired nanocomposite were analyzed by Brunauer-Emmett-Teller and Fourier transform infrared spectroscopy, respectively. Electrochemical measurement was performed on stainless steel mesh prefabricated electrodes in 1 M KOH electrolyte solution. The B-T/Au nanocomposite prepared under 12 min laser irradiation displayed the highest hydrogen storage capacity (15 Cg^-1).     

Electrochemical hydrogen storage of expanded graphite decorated with TiO2 nanoparticles

The electrochemical hydrogen storage of expanded graphite (EG) decorated with TiO₂ nanoparticles (NPs) calcined at different temperatures has been investigated with the galvanostatic charge and discharge method. The TiO₂ NPs are deposited on and between the graphene-like nanosheets of EG by a sol-gel method. The morphology, structure, composition, and specific surface area of the samples were characterized. The electrochemical measurement reveals that the EG decorated with TiO₂ NPs calcined at 500 °C has a discharge capacity of 373.5 mAh/g which is 20 times higher than that of pure EG and quite appealing for the battery applications. The mechanism of enhancement of the electrochemical activity for the TiO₂-decorated EG could be attributed to the preferable redox ability and photocatalytic property of TiO₂ NPs.     

Green synthesis and characterization of SnO2, CuO,Fe2O3/activated carbon nanocomposites and their application in electrochemical hydrogen storage

The goal of this study is to produce environmentally friendly nanomaterials that have a high hydrogen storage capacity. The researchers in this study used inexpensive natural bitumen to produce activated carbon (substratum) and a green solution synthesis combustion method to produce CuO, Fe₂O₃, and SnO₂ nanoparticles using a Mint extract as the source material. Metal oxides such as CuO, Fe₂O₃ and SnO₂ are used to increase hydrogen storage capacity and Columbic efficiency. AC and AC/SnO₂, AC/CuO, and AC/Fe₂O₃ nanocomposites have been confirmed via XRD (X-ray diffraction), TEM (transmission electron microscopy), EDX (energy-dispersive X-rays), FT-IR (fourier transform infrared), scanning electron microscope (SEM), and adsorption and desorption analysis of N₂ (BET). In terms of discharge capacity, AC/CuO, AC/Fe₂O₃, and AC/SnO₂ display respective capacities of 2250, 2500, and 3600 mAh/g after 20 cycles, respectively. Of all the sample materials, the AC/SnO₂ nanocomposite with the highest hydrogen storage capacity has the lowest Columbic efficiency. This implies that a sample with 54% Columbic efficiency, such as AC/CuO nanocomposite, is a more suitable specimen.     

Investigation of porous silicon thin films for electrochemical hydrogen storage

In this study, nanoporous silicon (PS) layers have been elaborated and used for hydrogen storage. The effect of the thickness, porosity and specific surface area of porous silicon on the amount of hydrogen chemically bound to the nanoporous silicon structures is studied by Infrared spectroscopy (FTIR), cyclic voltammetry (CV), contact angle and capacitance –voltage measurements. The electrochemical characterization and hydrogen storage were carried out in a three-electrode cell, using sulfuric acid 3 M H₂SO₄ as electrolyte by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge. The results indicate the presence of two oxidation peaks at 0.2 V and 0.4 V on the anodic side corresponding to hydrogen desorption and a reduction peak at −0.2 V on the cathodic side corresponding to the sorption of hydrogen. Moreover, the EIS studies performed on PS electrode in 3 M H₂SO₄ show that the hodograph contains a semicircle at high frequency region and a line in the lower frequency zone. An equivalent circuit has been proposed; the values of the equivalent circuit elements corresponding to the experimental impedance spectra have been determined and discussed. Finally, the highest hydrogen storage in PS was 86 mAh/g. This storage capacity decreases by only 7% of the initial capacity value, after 40 cycles.     

Preparation and characterization of hydrogen storage medium (IMO/TPAC) and asymmetric supercapacitor (IMO/TPAC6TPAC) using imogolite (IMO) and biomass derived activated carbon from tangerine peel (TPAC) for renewable energy storage applications

The blooming of renewable energy technology is magnificent in order to overcome the shrinking availability of fossil fuels and global warming. Hydrogen is considered the most prominent clean and green energy carrier. Hence, the present work focuses on the preparation and characterization of imogolite (IMO) clay and highly porous-natured activated carbon derived from the Tangerine Peel (TPAC) nanocomposite. SEM exhibits the IMO/TPAC nanocomposite reveals the presence of IMO embedded at the surface of TPAC. From the BET studies, there is a profound enhancement for the specific surface area of IMO/TPAC nanocomposite (1323 m² g⁻¹) compared to pristine TPAC (902 m² g ⁻¹) and IMO (217 m² g ⁻¹). A 6.3 wt% hydrogen storage capacity was achieved at 70 °C and the same (6.3 wt%) amount of hydrogen desorption was noticed at 108 °C for the IMO/TPAC nanocomposite. The electrochemical hydrogen storage of the IMO/TPAC electrode exhibits a hydrogen discharge capacity of 2573 mAh/g at 41^st cycle with excellent columbic efficiency of 92.4%, capacitance retention of 86.2% and superior corrosion resistance of 20.3 mA/cm². The fabricated ASC exhibits a maximum specific capacitance of 183 F g⁻¹ and retains capacitance of 85.1% for 5000 cycles. The as-fabricated ASC has an excellent energy density of 125 Wh kg⁻¹ and power density of 2634 Wkg⁻¹ at a wide operating potential window of 2.1 V. This ASC could able to power blue and white LEDs. Hence, these excellent characteristics proved that the prepared nanocomposite may serve as an excellent energy storage material.     

Hydrogenation properties of MgH2- x wt% AC (x=0, 5, 10, 15) nanocomposites

Magnesium is considered as a promising candidate for hydrogen storage due to its high storage capacity (theoretical value ~ 7.6 wt%). Nanocomposites of Magnesium hydride and activated charcoal (AC) were prepared using ball milling method. These nanocomposites were characterized by XRD, TGA, DSC and SEM techniques. The TGA analysis show that the MgH₂-5 wt% AC nanocomposite exhibits dehydrogenation capacity of 7.45 wt% (which is very close to the storage capacity of MgH₂) and starts release of hydrogen at 140 °C temperature. The results from the Kissinger plot from DSC result showed that the activation energy for hydrogen desorption of MgH₂ with 5 wt% AC was reduced compared to those of as-received.     

A comparative study of the electrochemical hydrogen storage properties of activated carbon and well-aligned carbon nanotubes mixed with copper

We studied the electrochemical hydrogen storage properties of activated carbon (AC) material mixed with copper. The discharge capacity of AC–Cu electrode which reached 510 mAh/g after 384 cycles, is much higher than that of the CNT–Cu electrodes. The plateau of discharge potential for AC–Cu electrode was very long and flat and reached −0.88 V vs. Hg/HgO, which was far from the potential of copper oxidation. The discharge plateau gradually appeared and continually lengthened with the increase of cycle number. Cyclic voltammetric experiments showed that the adsorption and desorption of hydrogen occurred on the surface of activated carbon and the active site increased with the increase of cycle number. The mechanism for electrochemical storage of hydrogen in AC–Cu electrode may be mainly physisorption.     

Composite sodium p-toluenesulfonate/polypyrrole/TiO2 nanotubes/Ti anode for sodium ion battery

Composite sodium p-toluenesulfonate/polypyrrole/TiO₂ nanotubes/Ti was designed and synthesized for sodium ion battery anode via facile electrochemical methods. The obtained composite sodium p-toluenesulfonate/polypyrrole/TiO₂ nanotubes/Ti (TsONa/PPy/TiO₂NT/Ti) electrode was investigated in terms of SEM, EDX, FTIR, galvanostatic charge/discharge and AC impedance. As expected, the composite TsONa/PPy/TiO₂NT/Ti electrode displayed higher electrochemical performances than the bare TiO₂NT/Ti electrode. For example, the reversible capacity after 50 cycles was still as high as about 200 mAh/g, higher than 170 mAh/g of TiO₂NT/Ti electrode. High Na-storage activities of both TiO₂NT and TsONa/PPy, high conductivity of TsONa-doped PPy and the synergy effect among the various components may be responsible for the improved electrochemical performances.     

Reactivity of TiH2 hydride with lithium ion: Evidence for a new conversion mechanism

The electrochemical reactivity of the face centered cubic (fcc) TiH₂ hydride with lithium ion was studied. A full discharge capacity of 1072 mAh/g at an average potential of 0.2 V can be achieved when the TiH₂ hydride electrode is ground with 10wt% of carbon. From X-ray diffraction (XRD) characterization of the electrodes, dehydrogenation of the titanium hydride via an electrochemical process occurs following different reaction steps. From 0 to 0.34 Li, an fcc δ-TiH_2−x solid solution is formed according to the reaction δ-TiH₂ (fcc) + 0.34 Li → δ TiH_1.66 (fcc) + 0.34 LiH. Pursuing the dehydrogenation process from 0.34 to 1, the cubic solid solution δ-TiH_2−x reacts with lithium ion and transforms partially in a distorted face centered orthorhombic phase δ-TiH (fco). At this stage, the absence of hexagonal close-packed (hcp) α-Ti formation is attributed to the peritectic transformation: hcp α-Ti(H) + fcc δ-TiH_2−x → δ-TiH. From 1 to 2 Li, a usual conversion mechanism is observed leading to the formation of hcp α-Ti and LiH according to the reaction δ-TiH_2−x (fcc) ↔ δ-TiH (fco) + Li → α-Ti (hcp) + LiH.     

The different effect of Co3O4 or/and carbon fiber originated from biomass on the electrochemical hydrogen storage performance of Co2B alloy

Co₂B alloy was synthesized via the method of high temperature solid phase. Carbon fiber (CF) was prepared from cotton by calcination process. The addition of carbon fiber and Co₃O₄ improves corrosion resistance and charge transfer speed of the composite material electrode. The R_ct value of Co₂B + 1 wt.% CF was 360 mΩ, lower than the other composite electrode could reduce charge transfer resistance. The overall electrochemical performance of Co₂B + 2 wt.% Co₃O₄ + 1 wt.% CF was best among all the electrodes, and its C_max could reach 715.3 mAh/g. The high conductivity and multiple reaction sites provided by carbon fiber and the catalytic effect of Co₃O₄ may be the main reasons for the improvement of electrochemical performance, which enhance the kinetic performance of electrochemical reactions. The synergistic effect of carbon fiber and Co₃O₄ improves the electrochemical hydrogen storage properties of Co₂B alloy. This work presents a simple and effective method to improve the electrochemical hydrogen storage performance of cobalt-boron alloys by adding transition metal oxides and carbon materials derived from biomass.     

Synthesis of reduced graphene oxide–TiO2 nanoparticle composite systems and its application in hydrogen production

The utilization of solar energy for the conversion of water to hydrogen and oxygen has been considered to be an efficient strategy to solve crisis of energy and environment. Here, we report the synthesis of reduced graphene oxide–TiO₂ nanoparticle composite system through the photocatalytic reduction of graphite oxide using TiO₂ nanoparticles. Photoelectrochemical characterizations and hydrogen evolution measurements of these nanocomposites reveal that the presence of graphene enhances the photocurrent density and hydrogen generation rate. The optimum photocurrent density and hydrogen generation rate has been found to be 3.4 mA cm⁻² and 127.5 μmole cm⁻²h⁻¹ in 0.5 M Na₂SO₄ electrolyte solution under 1.5AM solar irradiance of white light with illumination intensity of 100 mW cm⁻². In graphene–TiO₂ nanocomposite, photogenerated electrons in TiO₂ are scavenged by graphene sheets and percolate to counter electrode to reduce H⁺ to molecular hydrogen thus increasing the performance of water-splitting reaction.     

Enhanced electrochemical hydrogen storage performance of titanate-based nanostructures synthesized by facile auto-combustion: Li2TiO3 nanostructures versus LaTiO3 nanoperovskites

Green energies are vital for near-future energy needs. Hydrogen is a promising secondary energy career that counted as a clean-burning fuel. However, hydrogen suffers from a low volumetric energy density at ambient temperature and pressure. This deficiency has been overcome by “solid-state hydrogen storage” technologies, where the hydrogen is adsorbed/absorbed - depending on the type of materials - on a solid surface. Mixed metal oxides (MMOs) particularly transition-based metal oxides have been recently developed for hydrogen adsorption with a superior affinity for hydrogen. Here, we demonstrated two nanosized-MMOs based on (mono-) perovskite structure, Li₂TiO₃, and LaTiO₃. These two MMOs are successfully synthesized via the auto-combustion method in the presence of starch fuel. After confirmation of their structures and morphologies, the samples are used for electrochemical hydrogen storage in an alkaline medium. The average particle diameters of Li₂TiO₃ and LaTiO₃ are calculated to be around 16.74 and 24.46 nm, respectively. The results indicate a higher discharge capacity of LaTiO₃ nanoperovskites (1140 mAh/g) as compared to Li₂TiO₃ nanoparticles (680 mAh/g); as confirmed primarily by cyclic voltammetry (CV), with the theoretical hydrogen capacities of 4.1% and 2.4%, respectively. We believe that novel MMOs can be potentially fulfilled the requirements of future energy targets, arranged and reported by US-department of energy (DOE).     

A novel lithium decorated N-doped 4,6,8-biphenylene for reversible hydrogen storage: Insights from density functional theory

Two-dimensional (2D) carbon-based (C-based) and carbon-nitrogen (C–N) materials have great potential in the energy harvest and storage fields. We investigate a novel carbon biphenylene (C468) consisting of four-, six- and eight-membered rings of sp² carbon atoms (Fan et al., Science, 372:852-6 (2021)) for hydrogen storage. Using first-principles based Density functional theory calculations, we study the geometrical and electronic properties of C468 and N-doped C468. Lithium (Li) atoms were symmetrically adsorbed on both sides of the substrate, and their adsorption positions were determined. The maximum gravimetric density of hydrogen (H₂) adsorbed symmetrically on both sides of Li atom was studied within the scope of physical adsorption process (−0.2 eV/H₂ ∼ −0.6 eV/H₂). Li-decorated C468 can adsorb 8 upper hydrogen molecules and 8 lower hydrogen molecules, and Li-decorated N-doped C468 can adsorb 9 upper hydrogen molecules and 9 lower hydrogen molecules. The gravimetric densities of Li-decorated C468 and Li-decorated N-doped C468 can reach 9.581 wt% and 10.588 wt%, respectively. Our findings suggest significant insights for using Li-decorated C468 and Li-decorated N-doped C468 as hydrogen storage candidates and effectively expand the application scope of C-based materials and C–N materials.