Biological ion channels rely on ions as charge carriers and unidirectional ion flow to produce and transmit signals. To realize artificial biological inspired circuitry and seamless human-machine communication, ion-transport-based rectification devices should be developed. In this research, poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) gel polymer electrolytes (GPEs) are assembled to construct a novel ionic diode, enabling ion rectification through ion-diffusion/migration that emulates biological systems. This ion rectification results from the different diffusion/migration behaviors of mobile ions transporting in the GPE heterojunction. The electrical tests of the GPE heterojunction reveal outstanding rectifying ratio of 23.11. The GPE ionic diode operates in wide temperature window, from −20 °C (anti-freezing) to 125 °C (thermal tolerance). The absence of redox reactions is verified in the cyclic voltammogram. The GPE ionic diodes are used to construct ionic logic gates for signal communication. Furthermore, rectification of a triboelectric nanogenerator and potential for synaptic devices are demonstrated.

An electrochromic device (ECD), which can switch between black and transmissive states under electrical bias, is a promising candidate for smart windows due to its color neutrality and excellent durability. Most of the black ECDs are achieved through a reversible electrodeposition and dissolution mechanism; however, they typically suffer from relatively poor cycling stability and a slow coloration/ bleaching time. Herein, we present a heat-insulating black ECD with a gel electrolyte that operates via reversible Ni−Cu electrodeposition and dissolution. With the adoption of a Cu alloying strategy and a compatible gel electrolyte, this two-electrode ECD (5.0 cm × 2.5 cm) can achieve a cycling stability of 1500 cycles with transmittance modulation up to 55.2% in short coloration (6.2 s) and bleaching times (13.2 s) at a wavelength of 550 nm. Additionally, the ECD can be switched from the transparent state (visible light transmittance: 0.566) to the opaque state (visible light transmittance: 0.003) within 1 min, reaching transmittance less than 5% across the visible−near-infrared spectrum (400−2000 nm) to efficiently block solar heat. Besides, in the voltage-off state, the black Ni−Cu alloy film can be sustained for more than 60 min (at room temperature, λ = 550 nm). Under infrared irradiation (170 W/m 2 ) for 30 min, the black ECD blocks up to 35.0% of infrared radiation, which not only effectively prevents the heat transmission for energy management but also finds potential applications for promoting indoor human health and indoor farming.

Formation of ionogels through in situ polymerization can effectively improve electrolyte processability; however, the curing process has been slow and oxygen‐sensitive. Considering the low oxygen solubility of poly(ionic liquid)s (PILs), in situ polymerized ionogels are designed to realize excellent electrolytes. Herein, two in situ polymerized ionogels (PIL A & PIL B) are formulated, and they can be rapidly photocured within a minute. The ionogels are highly transparent, stretchable, and exhibit excellent physicochemical stability, including thermal, electrochemical, and air stability, allowing them to perform in various conditions. Benefitting from these properties, two high‐performance electrochromic devices (ECDs) are assembled, with iron‐centered coordination polymer (FeCP) and tungsten oxide (P‐WO3) electrochromic materials, achieving high color contrast (45.2% and 56.4%), fast response time (1.5/1.9 and 1.7/6.4 s), and excellent cycling endurance (>90% retention over 3000 cycles). Attributed to the thermal robustness of the ionogels, the ECDs can also be operated over a wide temperature range (−20 to 100 °C). With the use of deformable substrates (e.g., ultrathin ITO glass), curved electrochromic eye protector and flexible electrochromic displays are realized, highlighting their potential use in futuristic wearables.

Solid‐state black electrochromic devices (ECDs) are promising for smart window applications, particularly when privacy protection and low leakage are required. Herein, a Ni–Cu salts/poly(vinyl alcohol) based organohydrogel electrolyte is developed with superior visible‐light transparency (83.8%), ionic conductivity (0.11 mS cm−1), and mechanical properties (tensile strength: 11.1 kPa, breaking strain: 242.6%). Due to the high viscosity of the organohydrogel electrolyte, a homogeneous Ni–Cu alloy film with a surface roughness of around 11.2 nm can be electrodeposited under −3 V for 5 min, and the resulting black color can be retained for over 350 min with a transmittance increase of only 5% at the voltage‐off state. The solid‐state rigid ECD exhibits an outstanding optical contrast between the transparent and colored states (visible light transmittance: 70.8% vs 0.085%), excellent cycling stability with over 90% retention of optical contrast after 2000 cycles. Finally, a flexible ECD is fabricated with the organohydrogel electrolyte and annealed indium tin oxide (ITO)‐coated polyethylene naphthalate (PEN) films as flexible and durable electrodes. It exhibits good mechanical flexibility with transmittance modulation degradation of 10% after 800 bending cycles and switching stability for 400 cycles with up to 43% optical contrast.