Optical and electrical properties of thin films of WO3 electrochemically coloured

Strong blue colouration has been induced in rf sputtered thin films of WO₃ by electrochemical injection of H⁺, Li⁺, and Ag⁺ ions from various solid and liquid electrolytes. Electrical conductivity and optical properties of the coloured films are reported. Comparison of these properties with those of single crystal tungsten bronzes of equivalent composition is made. Evidence, electrical and optical, for a non-uniform distribution of injected ions produced by relatively fast diffusion down grain boundaries in these polycrystalline WO₃ films is presented. A model for the optical absorption consisting of two components, due to (i) conduction electron intra-band transitions (in states close to crystalline surfaces) and (ii) transitions from unionized donor states to the conduction band (in the grain boundary phase), is tentatively proposed.     

Improving electrochromic behavior of spray pyrolised WO3 thin solid films by Mo doping

The effects of molybdenum [Mo] doping on the electrochromic behavior of spray pyrolised tungsten trioxide [WO₃] thin films have been studied. It has been observed that the color-bleaching kinetics, coloration efficiency, and stability of electrochromic WO₃ films are closely related to molybdenum doping concentration, apart from their microstructure and crystallinity. While a nominal 6.0 at.% molybdenum doping produces best electrochromic response in WO₃ films, the electrochemical stability is highest when the nominal concentration of molybdenum is about 2.0 at.%. The improved electrochromic behavior of the Mo doped WO₃ films has been explained from the improved H⁺ ion diffusion coefficient in the films during coloration and decoloration process.     

Fast electrochromic response and high coloration efficiency of Al-doped WO3 thin films for smart window applications

Herein, vertically aligned Al:WO₃ nanoplate arrays were directly grown on ITO glass by a facile electrodeposition method and annealed in an argon atmosphere at 450 °C for 2h. Besides, this study reports the influence of Al doping on the electrochromic properties of WO₃ film in detail. Electrochromic properties such as cyclic voltammetry, chronoamperometry and optical transmittance were analyzed by protonic insertion/extraction in the 1 M LiClO₄/propylene carbonate as an electrolyte. The noticeable reversible color changing from transparent to the blue can be realized under the potential bias of ±1.0 V. XRD studies show that the produces films have highly crystalline structure. The EDS results clearly confirm the incorporation of Al element into the WO₃ network. From the optical absorption measurement, direct band gap energies are calculated as 3.62 and 3.34 eV for the WO₃ and the Al:WO₃, respectively. Compared to the as-prepared WO₃, the Al:WO₃ film exhibits outstanding electrochromic performance, including wide optical modulation (55.9%), high coloration efficiency (148.1 cm²C^-1), quick reaction kinetics (1.23 s and 1.01 s for colored and bleaching times, respectively), good rate capability and cycle durability at a wavelength of 632.8 nm. EIS measurements based on a charge-transfer resistance reveal that the dramatic improvement in the electrochemically active surface is achieved in the Al:WO₃ film. The increase of active surface facilitates transport kinetics for electron and ion intercalation/deintercalation within the porous metal oxide to enhance coloration efficiency. Comparatively energy levels of the WO₃ and the Al:WO₃ electrochromic films are also represented. From the Mott-Schottky studies, it is estimated that the donor concentration of the films is of the order of 10²⁰ cm⁻³. Taken together, these results not only provide important insight into a promising electrode for electrochromic displays applications, but also offer an economic and effective strategy for manufacturing of other doped metal oxide films.     

A tungsten-trioxide/prussian blue complementary electrochromic cell with a polymer electrolyte

Optically variable windows (smart windows), which control the transmission of light into buildings and vehicles, are of interest both for the control of solar heat load and for privacy applications. Such windows are likely to utilize electrochromic technology to achieve optical control. An electrochromic device consisting of a cathodically colouring tungsten trioxide (WO₃) film, an anodically colouring Prussian blue (PB) film, and a polymer electrolyte was made. The polymer electrolyte was prepared from polyvinyl alcohol doped with H₃PO₄ and KH₂PO₄ to accommodate the conduction of both H⁺ and K⁺ ions. The electrochromic WO₃ and PB films functioned in a complementary way such that the device was coloured or bleached by the application of –0.5 V or +0.5 V (WO₃ films vs PB film), respectively. The spectral characteristics of the coloured device confirmed the complementary colouration of WO₃ and PB in the device.     

Rapid preparation and performances of garnet electrolyte with sintering aids for solid-state Li–S battery

Lithium-sulfur (Li–S) batteries are attractive due to their high theoretical energy density. However, conventional Li–S batteries with liquid electrolytes undergo polysulfide shuttle-effect and lithium dendrite formation during charge/discharge process, leading to poor electrochemical performance and safety issues. Garnet type Li₇La₃Zr₂O₁₂ (LLZO) solid-state electrolyte (SSE) restricts the penetration of polysulfides and exhibits high ionic conductivity at room temperature (RT). Herein, Li_6.5La₃Zr_1.5Nb_0.5O₁₂ (LLZNO) ceramic electrolyte using Li₃PO₄ (LPO) as sintering aids (LLZNO-LPO) is prepared by the rapid sintering method and is applied to construct a shuttle-effect free solid-state Li–S battery. The SSE displays high conductive pure cubic-LLZO phase; during the rapid sintering, LPO melts and junctions the voids between the grains, thus improves Li⁺ conductivity. As a result, the LLZNO-LPO ceramic electrolyte with Li⁺ conductivity of 4.3 × 10^?4 S cm^?1 and high critical current density (CCD) of 1.2 mA cm^?2 is obtained at RT. The Li–S solid-state battery which utilizes LLZNO-LPO ceramic electrolyte can deliver an initial discharge capacity of 943 mA h·g^?1 and 602 mA h·g^?1 retention after 60 cycles. In the same time, the initial coulombic efficiency is as high as 99.5%, indicating that the SSE can effectively block the polysulfide shuttle towards the Li anode and fulfill a shuttle-free Li–S battery.     

Heat treatment of amorphous electrochromic WO3 thin films deposited onto indium-tin oxide substrates

Electrochromic tungsten oxide thin films, obtained by vacuum evaporation, were studied before and after heat treatment between 25 and 250°C for 2 h in air. Electrochromic properties were investigated in acid electrolyte by simultaneous measurements of the electrical and optical parameters. A.c. complex impedance techniques and voltammetry were used to characterize the films from an electrical point of view. We observed an enhancement of the electrochromic response times during both coloration and bleaching after heat treatment carried out between 150 and 220°C. This phenomenon was associated with a decrease of the ohmic drop in the electrode and a continuous variation of the impedance diagrams of these electrochromic electrodes. Moreover, we observed that the diffusion coefficient of H⁺ ions into WO₃, obtained on colored thin films, increased as the electrochromic kinetics increased.     

Promoting the Li storage performances of Li2ZnTi3O8@Na2WO4 composite anode for Li-ion battery

In this work, a reasonable strategy for the construction of Li₂ZnTi₃O₈@Na₂WO₄ composite was employed to promote the Li storage performances of Li₂ZnTi₃O₈. The Li₂ZnTi₃O₈@Na₂WO₄ composites (5, 10, and 15 wt%) were then prepared by a solution dispersion method. The introduction of Na₂WO₄ does not change the structures of the samples and they show similar morphologies with particle sizes from 100 to 200 nm. Suitable amount of Na₂WO₄ modification effectively improves the electrochemical performance of Li₂ZnTi₃O₈. Li₂ZnTi₃O₈@Na₂WO₄ composites (0, 5, 10, and 15 wt%) deliver the discharge/charge capacities of 137.4/136.4, 164.2/162.3, 189.2/188.1, and 154.5/153.3 mAh g^?1 at 0.5 A g^?1 after 100 cycles, respectively. Li₂ZnTi₃O₈@Na₂WO₄ composites (10 wt%) has the highest reversible capacities among all samples. The Na₂WO₄ shell with an excellent electronic conductivity can reduce electrode polarization, decrease the charge transfer resistance, enhance the Li-ion diffusion coefficient of Li₂ZnTi₃O₈, and then improve the electrochemical kinetics of composites. In addition, the formation of Ti–O bonds at the interface can be helpful for the stabilization of the composite, being beneficial for the improvement of their cycling stabilities. These results reveal that Na₂WO₄ coating is a facile and effective strategy to promote the Li storage performance of Li₂ZnTi₃O₈.     

Influence of Ag incorporation on the structural,optical and electrical properties of ITO/Ag/ITO multilayers for inorganic all-solid-state electrochromic devices

Indium tin oxide/silver/indium tin oxide (ITO/Ag/ITO, IAI) multilayer structures were prepared by DC magnetron sputtering as a conductive transparent electrode for inorganic all-solid-state electrochromic devices. A thin layer of silver (Ag) with various thicknesses was inserted between two layers of ITO films. The XRD and SEM results revealed that the microscopic morphology of Ag film was closely related to the thickness. Besides, the electrical and optical properties of the IAI multilayers were significantly influenced by the Ag layer thickness. The optimized IAI multilayers demonstrated the best combination of electrical and optical properties with a figure of merit of 54.05 (sheet resistance of 6.14 Ω/cm²and optical transmittance of 90.83%) when the Ag film was 10 nm thick. In order to evaluate the IAI multilayers as a transparent electrode for electrochromic applications, two ECDs with the structures of ITO/NiO_x/LiPON/WO₃/ITO and ITO/NiO_x/LiPON/WO₃/IAI were prepared, and their electro-optical properties were characterized by cyclic voltammetry (CV), chronoamperometry (CA) and spectroscopic measurements. Compared with ECD the pure ITO top electrode (ITO/NiO_x/LiPON/WO₃/ITO), the ECD with the IAI top electrode (ITO/NiO_x/LiPON/WO₃/IAI) presented a slightly smaller optical modulation amplitude, but a faster switching speed. All our findings indicate that the IAI multilayer structure is a promising alternative to the ITO thin film for inorganic all-solid state electrochromic applications.     

Optimization of Lithium Content and Sintering Aid for Maximized Li+ Conductivity and Density in Ta‐Doped Li7La3Zr2O12

Ta‐doped cubic phase Li₇La₃Zr₂O₁₂ (LLZ) lithium garnet received considerable attention in recent times as prospective electrolyte for all‐solid‐state lithium battery. Although the conductivity has been improved by stabilizing the cubic phase with the Ta⁵⁺ doping for Zr⁴⁺ in LLZ, the density of the pellet was found to be relatively poor with large amount of pores. In addition to the high Li⁺ conductivity, density is also an essential parameter for the successful application of LLZ as solid electrolyte membrane in all‐solid‐state lithium battery. Systematic investigations carried out through this work indicated that the optimal Li concentration of 6.4 (i.e., Li_6.4La₃Zr_1.4Ta_0.6O₁₂) is required to obtain phase pure, relatively dense and high Li⁺ conductive cubic phase in Li_7?xLa₃Zr_2?xTa_xO₁₂ solid solutions. Effort has been also made in this work to enhance the density and Li⁺ conductivity of Li_6.4La₃Zr_1.4Ta_0.6O₁₂ further through the Li₄SiO₄ addition. A maximized room‐temperature (33°C) total (bulk + grain boundary) Li⁺ conductivity of 3.7 × 10^?4 S/cm and maximized relative density of 94% was observed for Li_6.4La₃Zr_1.4Ta_0.6O₁₂ added with 1 wt% of Li₄SiO₄.     

Alkali metal tungsten bronze-doped energy-saving glasses for near-infrared shielding applications

Tungsten bronze has attracted global attention for its applications in near-infrared (NIR)-shielding windows. Here, alkali metal tungsten bronze (M_xWO₃, M = one or two types of Li, Na, and K)-doped glasses are prepared by a simple melt-quenching method. Their structure and properties were characterized by XRD, Raman spectroscopy, XPS and UV–Vis–NIR spectrophotometry. The effects of M on their structure and the NIR shielding performance are investigated. The LiF sample has the best NIR shielding performance, but its visible transmittance is sacrificed due to its low quality. The glasses containing mixed Li⁺ and K⁺ cooperate to form a high-quality Li⁺/K⁺-codoped tungsten bronze, while the glasses containing mixed Li⁺ and Na⁺ compete for limited tungsten resources to form Li⁺- and Na⁺-doped tungsten bronzes separately. The research here is helpful for understanding the role of different alkali metal ions in bulk energy-saving glass and is hugely significant for the guidance of the future applications of energy-saving glass without films.     

Investigations on pure and Ag doped lithium lanthanum titanate (LLTO) nanocrystalline ceramic electrolytes for rechargeable lithium-ion batteries

The nano-crystalline Li_0.5La_0.5TiO₃ (LLTO) was prepared as an electrolyte material for lithium-ion batteries. The effect of Ag⁺ ion doping in three different concentrations were investigated: Ag_0.1Li_0.4La_0.5TiO₃, Ag_0.3Li_0.2La_0.5TiO₃, and Ag_0.5La_0.5TiO₃ along with Li_0.5La_0.5TiO₃. The prepared pure and Ag⁺ doped LLTO were subjected for structural, morphological, electrical and optical characterizations. The cubic superlattice structure of LLTO nano-powder was altered due to the Ag⁺ substitution tending towards a tetragonal phase. Increasing Ag⁺ substitution a complete tetragonal phase occurs in Ag_0.5La_0.5TiO₃. The average particle size of the prepared ceramic electrolyte ranged between 80 nm and 120 nm. The photoluminescence study reveals that the LLTO and Ag doped LLTO gives a blue emission peak. The size effect on grain and grain boundary resistance was observed and reported. With Ag⁺ substitution, the conductivity got decreased due to the impedance caused by Ag⁺ ions in the conducting path of Li⁺ ion. Among all the samples, Ag_0.5La_0.5TiO₃ shows maximum conductivity of the order of 10^?3 S cm^?1.     

Reaction mechanisms of lithium garnet pellets in ambient air: The effect of humidity and CO2

Li₇La₃Zr₂O₁₂ (LLZO) has been reported to react in humid air to form Li₂CO₃ on the surface, which decreases ionic conductivity. To study the reaction mechanism, 0.5‐mol Ta‐doped LLZO (0.5Ta–LLZO) pellets are exposed in dry (humidity ~5%) and humid air (humidity ~80%) for 6 weeks, respectively. After exposure in humid air, the formation of Li₂CO₃ on the pellet surface is confirmed experimentally and the room‐temperature ionic conductivity is found to drop from 6.45×10^?4 S cm^?1 to 3.61×10^?4 S cm^?1. Whereas for the 0.5Ta–LLZO samples exposed in dry air, the amount of formed Li₂CO₃ is much less and the ionic conductivity barely decreases. To further clarify the reaction mechanism of 0.5Ta–LLZO pellets with moisture, we decouple the reactions between 0.5Ta–LLZO with water and CO₂ by immersing 0.5Ta–LLZO pellets in deionized water for 1 week and then exposing them to ambient air for another week. After immersion in deionized water, Li⁺/H⁺ exchange occurs and LiOH H₂O forms on the surface, which is a necessary intermediate step for the Li₂CO₃ formation. Based on these observations, a reaction model is proposed and discussed.     

Phase transformation and grain-boundary segregation in Al-Doped Li7La3Zr2O12 ceramics

Cubic phase garnet-type Li₇La₃Zr₂O₁₂ (LLZO) is a promising solid electrolyte for highly safe Li-ion batteries. Al-doped LLZO (Al-LLZO) has been widely studied due to the low cost of Al₂O₃. The reported ionic conductivities were variable due to the complicated Al³⁺-Li⁺ substitution and Li_xAlO_y segregation in Al-LLZO ceramics. This work prepared Li_7?3xAl_xLa₃Zr₂O₁₂ (x = 0.00~0.40) ceramics via a conventional solid-state reaction method. The AC impedance and corresponding distribution of relaxation times (DRT) were analyzed combined with phase transformation, cross-sectional microstructure evolution, and grain boundary element mapping results for these Al-LLZO ceramics to understand the various ionic transportation levels in LLZO with different Al-doping amounts. The low conductivity in low Al-doped (0.12~0.28) LLZO originates from the slow Li⁺ ion migration (1.4~0.25 μs) in the cubic-tetragonal mixed phase. On the other hand, LiAlO₂ and LaAlO₃ segregation occur at the grain boundaries of high Al-doped (0.40) LLZO, resulting in a gradual Li⁺ ion jump (6.5 μs) over grain boundaries and low ionic conductivity. The Li_6.04Al_0.32La₃Zr₂O₁₂ ceramic delivers the optimum Li⁺ ion conductivity of 1.7 × 10^?4 S cm^?1 at 25 °C.     

Tunable oxygen vacancies in MoO3 lattice with improved electrochemical performance for Li-ion battery thin film cathode

MoO₃ is a kind of promising cathode material for lithium-ion batteries (LIBs), owing to its high specific capacity (279 mA h g⁻¹) and layered structure. However, low electrical conductivity and sluggish reaction kinetics results in poor rate and Li-ions storage capability. The introduction of oxygen vacancies (OVs) can promote Li⁺ diffusion, and produce great electrical conductivity. Here, we report a strategy to synergize the merits of OVs by pulsed laser deposition (PLD) by adjusting oxygen partial pressures (2～20 Pa). The appropriate OVs concentration not only significantly approves electrochemical performance but also increases pseudocapacitance contribution. The Li-ion diffusion coefficient of MoO_3−x is remarkably improved by one or two orders of magnitude compared with that of MoO₃. Therefore, this facile and efficient strategy on OVs could afford a reference for other metal oxides for high-performance electrode materials.     

Synthesis of Ga-doped Li7La3Zr2O12 solid electrolyte with high Li+ ion conductivity

Garnet-type Li₇La₃Zr₂O₁₂ (LLZO) Li⁺ ion solid electrolyte is a promising candidate for next generation high-safety solid-state batteries. Ga-doped LLZO exhibits excellent Li⁺ ion conductivity, higher than 1 × 10^?3 S cm^?1. In this research, the doping amount of Ga, the calcination temperature of Ga-LLZO primary powders, the sintering conditions and the evolution of grains are explored to demonstrate the optimum parameters to obtain a highly conductive ceramics reproducibly via conventional solid-state reaction methods under ambient air sintering atmosphere. Cubic LLZO phase is obtained for Li_6.4Ga_0.2La₃Zr₂O₁₂ powder calcined at low temperature 850 °C. In addition, ceramic pellets sintered at 1100 °C for 320 min using this powder have relative densities higher than 94% and conductivities higher than 1.2 × 10^?3 S cm^?1 at 25 °C.     

Effect of laser power density on the electrochromic properties of WO3 films obtained by pulsed laser deposition

Pulsed laser deposition (PLD) was used to prepare tungsten trioxide (WO₃) films on ITO substrates with a varying laser power density of 4.0–5.5 W/cm². XPS indicated that when the laser power density decreased, the peak positions of the W 4f and O 1s orbits shifted slightly to low energy due to the difference in oxygen vacancies. As the laser power density decreased, W⁶⁺ gradually replaced the lattice position of O^2?, increasing oxygen vacancies in the lattice. The transmittance modulated values (ΔT) were over 44% at 830 nm, indicating strong absorption by the WO₃ thin films in the near-infrared ray. The switching time of the WO₃ thin films between bleached states and coloured states decreased as the laser power density increased due to the amorphous structure, morphology, and lower oxygen deficiency at a high power density. The high ΔT and very fast switching time of t_b (1.09 s) and t_c (6.01 s) demonstrated the excellent electrochromic (EC) properties of the WO₃ films prepared by PLD.     

Effect of excess Li2S on electrochemical properties of amorphous li3ps4 films synthesized by pulsed laser deposition

Amorphous Li₃PS₄ films were synthesized by pulsed laser deposition (PLD) at room temperature using Li₃PS₄ targets with excess lithium and sulfur. Raman and X‐ray photoemission spectroscopies indicated that the Li₃PS₄ film synthesized with a stoichiometric amount of Li₃PS₄ target contained lithium‐deficient phases such as Li₄P₂S₆, Li_2?xS and sulfur due to composition deviation caused during the ablation process. The film synthesized with a 14% Li₂S‐excess target (Li_3.42PS_4.21) contained fewer impurities, and exhibited a higher ionic conductivity of 5.3 × 10^?4 S/cm at 298 K than the lithium‐deficient film (3.1 × 10^?4 S/cm). The target composition is an important factor for the fabrication of highly conductive Li₃PS₄ films for electrolytes in thin‐film batteries.     

Structure and microwave dielectric properties of Li(Al1-xLix)SiO4-x ceramics

Li(Al_1-xLi_x)SiO_4-x (x = 0.005, 0.01, 0.015, and 0.02) ceramics were synthesized via a traditional solid phase reaction method with different sintering temperatures. To determine the positions occupied by Li⁺ in the lattice, the defect formation energies and total energies of various sites of LiAlSiO₄ (LAS) occupied by Li⁺ were examined, and the energy of LAS systems were calculated using density functional theory of first-principle with the CASTEP module. The results demonstrated that the Al-sites occupied by Li⁺ had the lowest formation energies and total energy, so Li ⁺ should substitute Al³⁺. The impacts of replacing Al³⁺ with Li⁺ on the bulk density, sintering properties, phase composition, microstructure, and microwave dielectric properties of Li(Al_1-xLi_x)SiO_4-x (0 = x ≤ 0.02) ceramics were thoroughly studied. With Li⁺-doping, the sintering temperature decreased from 1300 °C (x = 0) to 1175 °C (x = 0.02), while the Q × f and τ_f values of LAS ceramics significantly increased. The Li(Al_0.99Li_0.01)SiO_3.99 ceramic was fully sintered at 1250 °C for 10 h to obtain excellent microwave dielectric properties: ε_r = 3.49, Q × f = 51,358 GHz, and τ_f = ?51.48 × 10^?6 °C^?1.     

Sc3+-doping effects on porous Li3V2(PO4)3/C cathode with superior rate performance and cyclic stability

An enhanced sol-gel combustion method was used to synthesize different porous Sc³⁺-doped Li₃V_2-xSc_x(PO₄)₃/C (x = 0.00, 0.05, 0.10 and 0.15) compounds. The substitution of Sc³⁺ into the V³⁺ sites of Li₃V_2-xSc_x(PO₄)₃/C expands the lattice volume along with the enlargement of Li⁺ diffusion channel, which is beneficial for Li⁺ transportation and ionic conductivity improvement. Besides, the Sc³⁺ doping content exhibits a great impact on the morphology of Li₃V_2-xSc_x(PO₄)₃/C composite. The pristine Li₃V₂(PO₄)₃/C are constituted of porous particles and nanorods, and the ratio of nanorods to particles can be controlled by adjusting the amount of Sc³⁺ doping since the ratio of nanorods to particles decreases with increasing Sc³⁺ doping content. When Sc³⁺ doping content increases to a certain level (x = 0.15, Li₃V_1.85Sc_0.15(PO₄)₃/C), the nanorods are hardly seen. Li₃V_1.90Sc_0.10(PO₄)₃/C with higher tapped density, better reversibility, smaller resistance and larger Li⁺ diffusion coefficient demonstrates outstanding rate performance and cyclic stability, together with high specific discharge capacities of 130.2 and 92.9 mAh g⁻¹ at 0.5 and 20 C, respectively. Furthermore, a superior specific discharge capacity of 85.8 mAh g⁻¹ was retained at 20 C following 1000 cycles. Overall, a novel approach for the preparation of high-performance Li₃V_2-xSc_x(PO₄)₃/C cathodes with different morphologies for lithium-ion batteries is provided.     

Effects of Sb-doped SnO2–WO3 nanocomposite on electrochromic performance

With the increase in global challenges related to energy depletion, there is significant emphasis on studies involving next-generation optoelectronic applications such as smart windows and electronic displays. In particular, electrochromic devices (ECDs) have been identified as strategic innovations for energy-saving “smart windows” to address these challenges. Despite this increased level of attentions, ECDs have not yet attained broad commercial acceptance because of their limited electrochromic (EC) properties including coloration efficiency (CE,< 30.0 cm²/C) and switching speeds (> 10.0 s). To address these limitations, critical effort is required to enhance the EC properties by tuning the film structure and electronic structure of ECDs. In this study, we demonstrated the effect of nanocomposite structure of conductive metal oxides and WO₃ EC films. Antimony-doped tin oxide nanoparticles (ATO NPs) were utilized because of their superior electrical conductivity and large band gap. To achieve the optimum addition amount of ATO NPs in EC films, we adjusted the amount as 0, 0.6, 1.2, 2.4 wt%. WO₃ EC films with the optimum addition amount (1.2 wt%) of ATO NPs exhibited improved EC performance including both the switching speeds (5.4 s for the coloration speed and 2.4 s for the bleaching speed) and CE value (48.2 cm²/C). The enhancement of EC performance was attributed to the well-dispersed ATO NPs in the WO₃ films that can effectively improve electrical conductivity via the formation of by forming preferred electron pathway. In addition, the large band gap of ATO NPs broadens the transmittance modulation of the EC layer which contributed to the increment of the CE value. Therefore, our results suggest a strategy to obtain the enhanced WO₃ films with superior EC performances using conductive metal oxides nanocomposite structure.