Electrochromic materials have great application in soft displays and devices, but the application of ideal electrochromic textiles still faces challenges owing to the inconvenience of a continuous power supply. Here, electrochromic color-memory microcapsules (ECM-Ms-red, -yellow, and -blue) with a low drive voltage (2.0 V), coloration efficiency (921.6 cm2 C–1), a practical response rate (34.4 s–1), multistage response discoloration, and good color-memory performance (>72 h) and reversibility (≥1000 cycles) are developed. The color-memory performance is controlled by the energy difference of oxidation–reduction reactions. A multicolor and multistage response electrochromic color-memory wearable smart textile and flexible display are developed that are convenient and energy-efficient for application. The design philosophy of color-memory based on controllable energy difference of reactions has great potential application in sensors and smart textiles.

The diversification of electrochromic materials greatly expands the application fields of electrochromic devices. However, highly flexible electrochromic materials remain challenging due to the inherent limitations associated with the existing electrochromic processes. Inspired by the hydrogen bonding effect in the hydrogel structure, a highly elastic and bistable electrochromic ionic gel based on a hydrogen bonding cross-linking network is prepared by solution polymerization having excellent tensile resilience, uniform coloring, reversible switching (≤24.3 s), maximum transmittance change (≥80%), bistability (54 h), reversibility (>500 cycles), and coloration efficiency (≥85.3 cm2·C–1). This method has been used to develop bistable electrochromic displays. The unconventional exploration of the bistable design principle may provide a new idea for the realization of bistable electrochromic devices.

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A novel polymer microcapsule-filled dye-doped liquid crystal (DDLC) and phase-change material (PCM) system inspired by biological materials was first proposed, which was further encapsulated into a calcium alginate substrate by wet spinning for making an electrochromic fiber with both bistable electric–optical capability and knitting characteristics. Results show that the optical appearance of the optimized microcapsules and fiber can be reversibly changed between colored and colorless states according to the electric field by switching the DDLCs between isotropic (I) and anisotropic (A) states. Moreover, both I and A states can remain stable for more than 1 week after removing the electric field, due to the synergy of the greatly increased spatial hindrance of the PCM with core loading of 22.58% and the confinement effect from the polymer microcapsule shell material. Aside from the long-term optical stability, the high content of the densely packed DDLCs also endows the electrochromic fiber with a satisfactory driving voltage of 9.7 V, which is below the human safe voltage, showing great potential in a wide range of applications, such as flexible displays, energy-saving smart windows, and wearable advanced textiles.

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