An Electrochromic Nickel Phosphate Film for Large-Area Smart Window with Ultra-Large Optical Modulation

Abstract

Exploring materials with high electrochemical activity is of keen interest for electrochemistry-controlled optical and energy storage devices. However, it remains a great challenge for transition metal oxides to meet this feature due to their low electron conductivity and insufficient reaction sites. Here, we propose a type of transition metal phosphate (NiHPO4·3H2O, NHP) by a facile and scalable electrodeposition method, which can achieve the capability of efficient ion accommodation and injection/extraction for electrochromic energy storage applications. Specifically, the NHP film with an ultra-high transmittance (approach to 100%) achieves a large optical modulation (90.8% at 500 nm), high coloration efficiency (75.4 cm2 C−1 at 500 nm), and a high specific capacity of 47.8 mAh g−1 at 0.4 A g−1. Furthermore, the transformation mechanism of NHP upon electrochemical reaction is systematically elucidated using in situ and ex situ techniques. Ultimately, a large-area electrochromic smart window with 100 cm2 is constructed based on the NHP electrode, displaying superior electrochromic energy storage performance in regulating natural light and storing electrical charges. Our findings may open up new strategies for developing advanced electrochromic energy storage materials and smart windows.

Temperature Sensors Integrated with an Electrochromic Readout toward Visual Detection

“…Temperature is an important measurement parameter in many fields, including agricultural planting, mechanical engineering, human health, and electronic information. − Temperature sensors that can quickly determine the temperature are essential for obtaining critical information on measured objects. , Nowadays, most reported works have only focused on developing high-performance temperature sensors with higher sensitivity, faster response times, and higher repeatability . However, to translate signals into human-identifiable data, these temperature sensors often require bulky equipment or wired connections and cannot respond immediately to direct external stimuli, restricting their application in portable and real-time detection, especially at harsh external environments. , The inability to respond instantly to direct stimuli restricts their application in portable and real-time detection, especially at harsh external environments.…”

Tunable Interaction between Zn2+ and Superstructured Nb18W16O93 Bimetallic Oxide for Multistep Tinted Electrochromic Device

“…To date, many efforts have been devoted to circumventing the above issues to obtain ECDs with an excellent electrochromic performance by exploring novel electrochromic materials or devices. For instance, bimetallic NiCoO 2 film was proposed in our recent work, achieving a broad spectrum optical modulation over the visible–near-infrared (vis–NIR) range . Apart from that, newly developed Nb 18 W 16 O 93 bimetallic oxide exhibits tungsten bronze-like oxide superstructures with a characteristic of corner- and edge-sharing NbO 6 and WO 6 octahedra and partial filling by −W–O– chains.…”

“…For instance, bimetallic NiCoO 2 film was proposed in our recent work, achieving a broad spectrum optical modulation over the visible−near-infrared (vis−NIR) range. 18 Apart from that, newly developed Nb 18 W 16 O 93 bimetallic oxide exhibits tungsten bronze-like oxide superstructures with a characteristic of corner-and edge-sharing NbO 6 and WO 6 octahedra and partial filling by −W−O− chains. This unique structure can facilitate ion insertion/ extraction under a small electric field.…”

“…NiHPO 3 ·3H 2 O is a desirable counter-electrode material in this semisolid ECD owing to neglected color change and high transmittance in the Zn 2+ -based electrolyte. In addition, it also shows good electrochemical performance in our recently reported work . The obtained device exhibited a reversible electrochromic process at a potential range from −0.5 to 4.5 V at 20 mV s –1 (Figure b).…”

“…In addition, it also shows good electrochemical performance in our recently reported work. 18 The obtained device exhibited a reversible electrochromic process at a potential range from −0.5 to 4.5 V at 20 mV s −1 (Figure 4b). Meanwhile, the semisolid ECD presents independent and dynamic optical modulation in UV, vis, and NIR regions by applying different voltages (Figure 4c).…”