LiClO4-propylene Carbonate Electrolyte Research Articles

Enhanced lithium electrochromic performance of tungsten oxide films by rapid co-synthesis of iron and tantalum oxides using cold atmospheric pressure plasma polymerization

Lithium electrochromic performance of organo-tungsten oxynitride (WOz1Cz2Nz3) films enhanced by additions of organo-iron oxynitride (FeOz1Cz2Nz3) or organo-tantalum oxynitride (TaOz1Cz2Nz3) with an atmospheric pressure plasma jet (APPJ) by a rapid deposition onto 60 Ω/square flexible polyethylene terephthalate (PET)/indium tin oxide (ITO) substrate at a short exposed duration of 54 s has been investigated. Flexible organo-tungsten-iron-tantalum oxynitride (WFexTayOz1Cz2Nz3) film possesses the significant Li+ ionic electrochromic performance, even though after being bent 360° around a 2.5-cm diameter rod for 1000 times and tested for 200 cycles of reversible Li+ ion intercalation and de-intercalation in a 1 M LiClO4-propylene carbonate electrolyte respectively by the potential sweep switching from the potential 2 V to − 1 V at a scan rate of − 40 mV/s and from the potential − 1 V to 2 V at a scan rate of 40 mV/s and by the potential step altering at the potential − 1 V for 20 s and the potential 2 V for 30 s, respectively. Li+ ionic intercalated charge of up to 13.2 mC/cm2 and optical modulation of up to 64.8% at a wavelength of 850 nm are proven for WFexTayOz1Cz2Nz3 film, respectively.

Enhanced lithium intercalation and conduction in LiαFeTaxOyCz films by the addition of lithium oxides with an atmospheric pressure plasma jet

An enhancement of lithium ionic intercalation and conduction performance of lithiated-organo-iron-tantalum oxide (LiαFeTaxOyCz) films has been accomplished by the addition of organo-lithium oxides (LiOyCz) into organo-iron-tantalum oxide (FeTaxOyCz) films using an atmospheric pressure plasma jet (APPJ) at various mixed concentrations of lithium tert-butoxide [(CH3)3COLi] and tantalum ethoxide [Ta(OC2O5)5] precursors. The rapid deposition of LiαFeTaxOyCz films onto polished stainless steel substrates at short exposed durations of 38–41 s with an APPJ has been investigated. The APPJ-polymerized LiαFeTaxOyCz films have noticeable Li+ ionic intercalation/deintercalation performance at 200 reversible cycles in a 1-M LiClO4-propylene carbonate electrolyte as analyzed by both potential sweep and potential step in situ Li+ ionic intercalation. The Li+ ion intercalated and deintercalated charges are significantly improved from 5.70 and 5.20 mC/cm2 for FeTaxOyCz film to 8.11 and 7.51 mC/cm2 for LiαFeTaxOyCz films, respectively. The Li+ ionic conduction performance of FeTaxOyCz film is slightly enhanced from 107 × 10−10 to 118 × 10−10 S/cm for LiαFeTaxOyCzfilm, as verified by electrochemical impedance spectroscopy in the devices of polyethylene terephthalate (PET)/indium tin oxide (ITO)/NiOx/FeTaxOyCz/NiOx/ITO and PET/ITO/NiOx/LiαFeTaxOyCz/NiOx/ITO.

Highly reversible crystal transformation of anodized porous V2O5 nanostructures for wide potential window high-performance supercapacitors

The advancement of efficient pseudocapacitive electrodes is a formidable challenge. In this study, we fabricated a binder-free porous network of vertically aligned V2O5 nanochannels via the simple and economical electrochemical anodization of vanadium foil. Reversible charge storage and the structural transformation of V2O5 during successive reduction and oxidation cycles was confirmed through X-ray diffraction analysis. We used several electrochemical techniques to study pseudocapacitive charge storage within the active sites of the porous network and rapid charge transfer through the vertical V2O5 channels in a 1 M LiClO4–propylene carbonate electrolyte. The as-prepared V2O5 electrode was studied over a wide potential window of 1.5 V, and it exhibited a specific capacitance of 840 F g−1 at 4 A g−1. A rate capability of 48% was observed with an eight-fold increase in the current density, and the electrode retained 90% of its capacitance after 5500 CV cycles. This performance indicated that the porous structure was highly retained, as confirmed through microstructural analysis after cycling. The V2O5 electrode presented herein may provide new options for replacing electrodes in next-generation supercapacitors.

Lithium intercalation and conduction in Fe-containing tantalum oxide films synthesized with an atmospheric pressure plasma jet

Lithium ionic intercalation and conduction performance of tantalum oxides films improved by adding with iron oxides using an atmospheric pressure plasma jet (APPJ) is investigated. Precursors [tantalum ethoxide, Ta(OC2H5)5]2] and ferrocene [Fe(C5H5)2] vapors are carried by argon gas, mixed by oxygen gas and injected into air plasma torch for rapid synthesis of organo-tantalum-iron oxides (TaFexOyCz) films onto the polished stainless steel substrate at a short exposed-duration of 35 s. The APPJ-synthesized TaFexOyCz films possess the prominent Li+ ionic intercalation performance for 200 cycles of reversible Li+ ionic intercalation and deintercalation in a 1 mol/L LiClO4-propylene carbonate electrolyte by switching measurements with a potential sweep from − 1.25 to 1.25 V at a scan rate of 40 mV/s. After 200 cycles of reversible Li+ ionic intercalation and deintercalation, the Li+ ions intercalated and deintercalated charges are respectively increased from 2.41 and 1.91mC/cm2 for TaOyCz film to 5.69 and 5.23 mC/cm2 for TaFexOyCz film. The Li+ ionic conduction performance of TaOyCz film is highly enhanced from 5.76 × 10−11 to 1070 × 10−11 S/cm for TaFexOyCz film, while proven by electrochemical impedance spectroscopy in the devices of polyethylene terephthalate (PET)/indium tin oxide (ITO)/NiOx/TaOyCz/NiOx/ITO and PET/ITO/NiOx/TaFexOyCz/NiOx/ITO.

Flexible electrochromic tungsten/iron mixed oxide films synthesized by an atmospheric pressure plasma jet

Flexible electrochromic organo-tungsten-iron oxide (WFexOyCz) films are rapidly deposited onto flexible (60 Ω/□ polyethylene terephthalate/indium tin oxide; PET/ITO) substrates by a low temperature-atmospheric pressure-plasma polymerization method with an atmospheric pressure plasma jet (APPJ) for a short exposed duration of 48 s. The precursor vapors of tungsten hexacarbonyl [W(CO)6] and biscyclopentadienyl iron [ferrocene; Fe(C5H5)2] are mixed with O2 gases at various gas flow rates, injected into air plasma jet and sprayed onto PET/ITO substrates at room temperature (~23 °C) and at atmospheric pressure (1.013 × 105 Pa). Flexible electrochromic WFexOyCz films are synthesized with a specific addition of oxygen gases with superior lithium electrochromic properties as demonstrated by a potential sweep alternating between −1 V and 2 V at a scan rate of 40 mV/s in a 1 M LiClO4-propylene carbonate electrolyte. With amorphous WFexOyCz films produced with an APPJ by adding oxygen gases at a specific flow rate of 0.5 sccm, a high value in oxygen deficiency up to 0.189 allows more Li+ ions to intercalate into and deintercalate out of the film. Significant coloration and bleaching are proven by the high values in optical transmittance modulation (ΔT) of up to 70.3%, optical density (ΔOD) up to 0.77 and color efficiency (η) up to 61.3 cm2/C, at a wavelength of 800 nm, respectively.

Lithium ionic intercalation and conduction performance of flexible-lithiated-iron oxides films synthesized by low temperature-atmospheric pressure-plasma polymerization

The lithium ionic intercalation and conduction performance of flexible-organo-lithiated iron oxide (LixFeOyCz) films enhanced by addition of organo-lithium oxides (LiOyCz) into organo-iron oxide (FeOyCz) films by an atmospheric pressure plasma jet (APPJ) at various mixed concentrations of ferrocene [Fe(C5H5)2] and lithium tert-butoxide [(CH3)3COLi] precursors are investigated. A rapid deposition of LixFeOyCz films onto 40 Ω/square flexible polyethylene terephthalate (PET)/indium tin oxide (ITO) substrates at short exposed durations of 37–38 s with an APPJ has been reported. The APPJ-polymerized LixFeOyCz films possess outstanding Li+ ionic intercalation performance in a 1 M LiClO4-propylene carbonate electrolyte as characterized both by potential sweep and potential step in situ Li+ ionic intercalation. The Li+ ionic intercalated (deintercalated) charge of 7.73 (6.28) mC/cm2 for FeOyCz films is advanced to 11.59 (11.22) mC/cm2 for LixFeOyCz films. The superior Li+ ionic conduction performance of LixFeOyCz films has been demonstrated by electrochemical impedance spectroscopy in the device of PET/ITO/NiOx/LixFeOyCz/NiOx/ITO, while the Li+ ionic conductivity of up to 793.0 × 10−10 S/cm at 10% of lithium tert-butoxide precursor addition is accomplished.

Electrochemical behavior of nickel–polyaniline electrode in 1 M LiClO4–propylene carbonate electrolyte

Doping of emeraldine-base (EB) with lithium salts involves the addition of lithium cations to nitrogen in imine groups and intercalation of counter ions i.e., proceeds similarly to doping with protonic acids. The results of studies show that doping of polyaniline (PANI) with a lithium salt proceeds relatively difficultly as compared with protonic doping. For a polyaniline electrode, to attain faster the stationary mode by repeated cycling (“electrode training”) in an organic lithium electrolyte and to reach the higher capacitance, the method of preliminary lithiation of the NiO surface layer on the nickel substrate with Li+ cations through the EB film is proposed. The studies show that preliminary cycling of the Ni/PANI electrode (7 cycles at 10 mV s–1) in the region of negative potentials (from 0 to–2.99 V vs. Ag/AgCl) leads to substantial increase in the capacitance characteristics of the PANI film in the region of its intrinsic redox activity from–0.4 to +1.1 V at high charge–discharge currents (2–5 A/g).

Enhanced lithium ionic intercalation and conduction performance of flexible iron oxide films using an atmospheric pressure plasma jet

Enhancement on lithium ionic intercalation and conduction performance of flexible-organo-iron oxide (FeO y C z ) films, via a rapid co-synthesis with lithium oxides (LiO y C z ) onto 40 ohm/square flexible polyethylene terephthalate/indium tin oxide substrates at a short exposed duration of 35 s, using an atmospheric pressure plasma jet (APPJ) by mixed ferrocene [Fe(C5H5)2] and lithium tert-butoxide [(CH3)3COLi] precursors, was investigated. APPJ-synthesized-lithiated iron oxide (Li x FeO y C z ) films exhibit the prominent Li+ ionic intercalation performance in a 1 M LiClO4-propylene carbonate electrolyte potential analyzed both by potential sweep and potential step in situ Li+ ionic intercalation. The important Li+ ionic conduction performance of APPJ-synthesized Li x FeO y C z films is proven by electrochemical impedance spectroscopy in the device of PET/ITO/NiO x /Li x FeO y C z /NiO x /ITO. The Li+ ionic diffusion coefficient and conductivity of 1.16 × 10−10 cm2/s and 9.7 × 10−10 S/cm for FeO y C z films are, respectively, improved to 3.89 × 10−10 cm2/s and 838.0 × 10−10 S/cm for Li x FeO y C z films even after being bent 360° around a 2.5-cm-diameter rod for 1000 cycles.

Enhanced electrochromic performance of flexible WFexOyCz films by O2 gas addition using low temperature plasma polymerization

An investigation was conducted into the prominent lithium electrochromic performance of flexible organo-tungsten-iron oxide (WFexOyCz) films deposited onto flexible (60 Ω/□ polyethylene terephthalate/indium tin oxide) substrates. The simple one-step low temperature (∼23 °C) plasma polymerization method was used to inject the precursors tungsten hexacarbonyl [W(CO)6] and biscyclopentadienyl iron [Fe(C5H5)2] into the plasma chamber, whilst being mixed with O2 gases at various gas flow rates. The plasma-polymerized WFexOyCz films at a certain addition of oxygen gases achieved outstanding lithium electrochemical reversibility of Li+ ion intercalation and de-intercalation proven by a potential sweep switching between −1 V and 1 V at a scan rate of 50 mV/s in a 1 M LiClO4-propylene carbonate electrolyte. High values for optical transmittance modulation (ΔT) of up to 83.2%, optical density (ΔOD) of up to 1.08 and color efficiency (η) of up to 62.3 cm2/C at a wavelength of 854.9 nm were obtained for the amorphous WFexOyCz films synthesized by the addition of oxygen gases at a flow rate of 17 sccm. The results verified that the proper addition of oxygen gas provides a suitable routine to enhance the electrochromic properties of plasma-polymerized WFexOyCz films.

Synthesis of samarium telluride thin films by successive ionic layer adsorption and reaction (SILAR) method for supercapacitor application

The present paper deals with synthesis of samarium telluride (Sm2Te3) thin films using simple and low cost successive ionic layer adsorption and reaction (SILAR) method for supercapacitor application. The Sm2Te3 thin films are characterized by X-ray diffraction (XRD) for structural determination, energy dispersive analysis of X-ray (EDAX) for elemental composition, field emission scanning electron microscopy (FE-SEM) for surface morphological study and contact angle measurement for wettability study. The Sm2Te3 exhibits orthorhombic crystal structure with cloud like surface morphology. The film surface showed lyophilic behavior with contact angle of 5.7° for propylene carbonate (PC). Further, electrochemical measurements are carried out in LiClO4–PC electrolyte using cyclic voltammetry (CV), galvanostatic charge discharge and electrochemical impedance spectroscopy (EIS) techniques. The Sm2Te3 film showed maximum specific capacitance and energy density of 144Fg−1 and 10Whkg−1 respectively. The EIS study showed negligible change in resistive parameters after 1000 electrochemical cycles.

One-step chemical synthesis of samarium telluride thin films and their supercapacitive properties

The letter reports synthesis of samarium telluride (Sm2Te3) thin films through a one-step chemical route. The formation of Sm2Te3 is confirmed by X-ray diffraction and X-ray photoelectron spectroscopy studies. The surface morphological study is carried out using field emission scanning electron microscopy and contact angle measurement techniques. The film shows barley-like microstructure with an average length of barley of about 5μm and diameter of about 300nm. The Sm2Te3 film surface exhibits lyophilic nature with contact angle of 21.3° for propylene carbonate electrolyte. Cyclic voltammetry results revealed specific capacitance of 207Fg−1 with power density of 14.18kWkg−1 in LiClO4-propylene carbonate electrolyte.

Enhanced lithium-ion intercalation and conduction of transparent tantalum oxide films by lithium addition with an atmospheric pressure plasma jet

An investigation is conducted on enhancing lithium-ion intercalation and conduction performance of transparent organo tantalum oxide (TaO y C z ) films, by addition of lithium via a fast co-synthesis onto 40 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates at the short exposed durations of 33–34 s, using an atmospheric pressure plasma jet (APPJ) at various mixed concentrations of tantalum ethoxide [Ta(OC2H5)5] and lithium tert-butoxide [(CH3)3COLi] precursors. Transparent organo-lithiated tantalum oxide (Li x TaO y C z ) films expose noteworthy Li+ ion intercalation and conduction performance for 200 cycles of reversible Li+ ion intercalation and deintercalation in a 1 M LiClO4-propylene carbonate electrolyte, by switching measurements with a potential sweep from −1.25 to 1.25 V at a scan rate of 50 mV/s and a potential step at −1.25 and 1.25 V, even after being bent 360° around a 2.5-cm diameter rod for 1000 cycles. The Li+ ionic diffusion coefficient and conductivity of 6.2 × 10−10 cm2/s and 6.0 × 10−11 S/cm for TaO y C z films are greatly progressed of up to 9.6 × 10−10 cm2/s and 7.8 × 10−9 S/cm for Li x TaO y C z films by co-synthesis with an APPJ.

Direct one-step synthesis of flexible electrochromic tungsten/iron mixed oxide films onto flexible PET/ITO substrates using low temperature plasma polymerization

An investigation has been undertaken into the improved lithium electrochromic performance of flexible tungsten oxide films by the addition of iron oxides via one step synthesis onto flexible 60 Ω/square polyethylene terephthalate/indium tin oxide substrates using a low temperature plasma polymerization method. The flexible organic–inorganic hybrid nanocomposite WOyCz, WFexOyCz and FeOyCz films are synthesized by injecting the precursors tungsten carbonyl [W(CO)6] and/or ferrocence [Fe(C5H5)2] into the plasma chamber. The capable fractions of the nano-grain boundaries between the nano-grains produced in the WOyCz and WFexOyCz films assure the reversible Li+ intercalation and deintercalation properties. The addition of iron oxides into tungsten oxide films at a certain Fe gas flow ratio enhances the optical modulation (ΔT) from 74.4 to 80.7 %, increases the optical density (ΔOD) from 0.71 to 0.92, and raises the color efficiency (η) from 48.8 to 56.6 cm2/C, respectively, at a wavelength of 721 nm, even after 200 cycles of reversible Li+ ion intercalation/de-intercalation in a 1 M LiClO4-propylene carbonate electrolyte.

Lithium electrochromic performance of flexible Ni oxide films enhanced by Fe oxide addition with an atmospheric pressure plasma jet for flexible electrochromic application

Lithium electrochromic performance of flexible organo-nickel oxide (NiO y C z ) films enhanced by a rapid co-deposition with organo-iron oxide (FeO y C z ) onto 40 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates at a short exposed duration of 32 s using an atmospheric pressure plasma jet (APPJ) at various gas flow ratios of ferrocence [Fe(C5H5)2] precursors added onto nickelocence [Ni(C5H5)2] precursors is investigated. The APPJ-synthesized organo-nickel-iron oxide (NiFe x O y C z ) films possess notable electrochromic performance for 200 cycles of reversible Li+ ion intercalation and deintercalation in a 1 M LiClO4-propylene carbonate electrolyte by the switching measurements of potential sweep from −1.25 to 1.25 V at a scan rate of 50 mV/s and the potential step at −1.25 and 1.25 V. The optical modulation (∆T) of 27.6 % for NiO y C z films with a thickness of 299 nm at a wavelength of 463.6 nm is highly improved up to of 46.8 % for NiFe x O y C z films with a thickness of 313 nm as synthesized with an APPJ at atmospheric pressure and room temperature (~23 °C).

Facile synthesis of Sm2S3 diffused nanoflakes and their pseudocapactive behavior

The Sm2S3 thin films with diffused nanoflakes morphology are prepared by an environment-friendly facile chemical synthesis method and used in electrochemical supercapacitors. The structural, elemental and surface morphological characterization are carried out using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and wettability techniques. The FESEM images show tree root like distribution of flakes with average flake width of about 80nm. The film surface is lyophilic with propylene carbonate contact angle of 21°. The supercapacitive measurements are carried out through cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The Sm2S3 film electrode exhibited a highest specific capacitance (Cs) of 213 Fg−1 at 5mVs−1 scan rate in LiClO4-propylene carbonate electrolyte. Asymmetric nature of charge–discharge curves confirmed pseudocapacitive behavior of electrode with energy and power densities of 39.39Whkg−1 and 4.33kWkg−1, respectively. An equivalent series resistance of 0.44Ωcm−2 indicated negligible ohmic losses in charge storage. An electrochemical stability of 81.47% is retained after 1000 cycles indicating that Sm2S3 is a promising candidate for supercapacitor application.

Lithium Electrochemical and Electrochromic Properties of Atmospheric Pressure Plasma Jet-Synthesized Tungsten/Molybdenum Mixed Oxide Films for Flexible Electrochromic Devices

Lithium electrochemical and electrochromic (EC) performances of flexible tungsten/molybdenum mixed oxide (WMo x O y C z ) films, deposited onto 40-Ω/square flexible polyethylene terephthalate/indium tin oxide substrates at room temperature (~23°C) and at the short exposed durations of 19-26 s using an atmospheric-pressure plasma-enhanced chemical vapor deposition with an atmospheric pressure plasma jet (APPJ) at various precursor injection angles, are investigated. The flexible organo-tungsten-molybdenum oxide (WMo x O y C z ) films have been identified for the remarkable EC performance for 200 cycles of reversible Li + ion intercalation and deintercalation in a 1-M LiClO 4 -propylene carbonate electrolyte by a potential sweep switching measurement between -1 and 1 V at a scan rate of 50 mV/s, even after being bent 360° around a 2.5-cm diameter rod for 1000 cycles. The optical modulation (AT) is up to of 75.6% at a wavelength of 691.9 nm for WMo x O y C z films cosynthesized with an APPJ.

Electrochromic Ni–Fe oxide thin films synthesized by an atmospheric pressure plasma jet for flexible electrochromic application

Flexible-electrochromic organo-nickel-iron oxide (NiFexOyCz) films deposited onto flexible polyethylene terephthalate (PET)/indium tin oxide (ITO) substrates using atmospheric-pressure plasma-enhanced chemical vapor deposition with an atmospheric pressure plasma jet under various flow rates of oxygen gases are investigated. Precursors [nickelocence, Ni(C5H5)2] and [ferrocence, Fe(C5H5)2] vapors are carried by argon gas, mixed by oxygen gas and injected into air plasma torch for a rapid synthesis of NiFexOyCz films by a short duration of the substrate, 32s, in the plasmas. Uniform light modulation on PET/ITO/NiFexOyCz is produced while the moving PET/ITO substrate is exposed to plasma torch at room temperature (~23°C) and atmospheric pressure. Light modulation with up to a 43.2% transmittance variation at a wavelength of 708nm even after 200cycles of Li+ intercalation and de-intercalation in a 1M LiClO4-propylene carbonate electrolyte is accomplished.

Modified chemical synthesis of porous α-Sm2S3 thin films

The paper reports synthesis of porous α-Sm2S3 thin films using modified chemical synthesis, also known as successive ionic layer adsorption and reaction (SILAR) method. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), wettability and ultraviolet–visible spectroscopy (UV–vis) techniques are used for the study of structural, elemental, morphological and optical properties of α-Sm2S3 films. An orthorhombic crystal structure of α-Sm2S3 is resulted from XRD study. The SEM and AFM observations showed highly porous α-Sm2S3 film surface. An optical band gap of 2.50eV is estimated from optical absorption spectrum. The porous α-Sm2S3 thin film tuned for supercapacitive behaviour using cyclic voltammetry and galvanostatic charge discharge showed a specific capacitance and energy density of 294Fg–1 and 48.9kWkg–1, respectively in 1M LiClO4–propylene carbonate electrolyte.

Lithium electrochromic properties of atmospheric pressure plasma jet-synthesized tungsten/molybdenum-mixed oxide films for flexible electrochromic device

An investigation is conducted into the enhanced lithium electrochromic performance of flexible tungsten/molybdenum-mixed oxide (WMo x O y C z ) films deposited onto 40 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates, using a low temperature (~23 °C) atmospheric pressure plasma-enhanced chemical vapor deposition with an atmospheric pressure plasma jet at various substrate distances. The rapid synthesis of flexible WMo x O y C z films is performed by injecting the mixed hexacarbonyl and precursors W(CO)6 and Mo(CO)6 into an air plasma jet and exposing the substrate in the plasmas for short exposure durations (19–34 s) at various substrate distances. The flexible WMo x O y C z films possess the remarkable Li+ ion electrochromic performance, even though after being bent 360° around a 2.5-cm diameter rod for 1,000 cycles and tested for 200 cycles of reversible Li+ ion intercalation and deintercalation in a 1-M LiClO4-propylene carbonate electrolyte, respectively, by a potential sweep switching at the scan rates of ±50 mV/s from the potential of −1 to 1 V and a potential step switching at the potentials of −1 and 1 V. Significant optical modulation and optical density change of up to 71.2 % and 0.73 at a wavelength of 622 nm are respectively achieved.

Enhanced lithium electrochromic performance of flexible tungsten oxide films by tantalum addition with an atmospheric pressure plasma jet

Enhanced lithium electrochromic performance of flexible tungsten oxide films by the addition of tantalum with an atmospheric pressure plasma jet in a rapid synthesis onto flexible 40Ω/□ polyethylene terephthalate/indium tin oxide substrates was investigated. The flexible organic–inorganic hybrid composites WOyCz, WTaxOyCz and TaOyCz films were synthesized by injecting the precursors tungsten carbonyl [W(CO)6] and/or tantalum ethoxide [Ta(OC2H5)] into an air plasma jet under an atmospheric pressure and the ambient temperature (~23°C). The addition of tantalum into tungsten oxide films improves the optical modulation (ΔT) from 62.3% to 74.8% (at a wavelength of 800nm, even after 200 cycles of reversible Li+ ion intercalation/de-intercalation in a 1M LiClO4-propylene carbonate electrolyte), reduces the coloration time from 13s to 8s, and increases the diffusion coefficient of the lithium ion from 0.4×10−10cm2/s to 1.2×10−10cm2/s.