Search

Energy crisis and worsening greenhouse effects cause unprecedented global environmental and economic‐sustainability challenges. The emerging all‐season thermal regulation technology that can provide comfort to humans without consuming external‐energy demonstrates promising prospects. Inspired by the temperature‐accommodative skin of the color‐changing rain‐frog, a biodegradable nature‐skin‐derived thermochromic membrane (PCTM‐H) is nano‐engineered for active all‐season thermal management using the integrative interfacially wet‐casting film‐forming and spraying strategy of nature‐skin to incorporate polyvinyl alcohol and thermochromic microcapsules. Its outstanding thermochromic origins allow it to switch adaptively between cooling and heating modes without additional energy input. PCTM‐H has a light color with high reflectivity in hot summer and a dark‐color that absorbs solar radiation in cold winter, with an overall visible light modulation of ≈53.5%, solar modulation of ≈32.2%, and a remarkable emissivity in mid‐infrared band (≈86.7%). PCTM‐H has exceptional adaptive thermal management capabilities for multitudinous outdoor‐applications. Simulation results show that PCTM‐H has prominent energy‐saving efficiency in cities with different climate zones when utilized as roof‐protection membranes. Additionally, the distinguished mechanical features, weatherability, and bio‐degradability of PCTM‐H substantially increase its potential applications. This study provides a reference for the development of active all‐season thermal management materials and high‐value utilization of nature‐skin, contributing to the goal of carbon‐neutrality. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) are recognized for energy conversion efficiency and applications including electronics and energy storage devices. This study introduces a groundbreaking development in TENG by incorporating negative Poisson's ratio metamaterials to fabricate auxetic‐assisted triboelectric nanogenerators (Auxetic‐TENG), subversively overcoming the low power density of traditional materials. Subtly, an integrated layer‐by‐layer‐assembly and core–shell accumulation strategy is employed to create a synclastic polytetrafluoroethylene negative friction shell‐skeleton, into which positive Poisson's ratio nature collagen aggregate (CA) foam is inwardly embedded as the positive friction core‐material. Surprisingly, the on‐demand introduction of metamaterials in synergy with CA significantly increases the contact area and mechanical energy absorption of the Auxetic‐TENG under pressure. This enhancement in the conversion efficiency of mechanical to electricity capitalizes on the contraction origins of negative Poisson's ratio metamaterials, integrated with the expansion characteristics of the positive Poisson's ratio materials within the structure, facilitating the synergistic compression of the positive and negative friction stratum. Consequently, Auxetic‐TENG achieves an open‐circuit voltage of 85 V, an overturning four times compared to conventional contact–separation TENG, and a power density of 4.2 W m−2. Application experiments demonstrate the superior performance of auxetic‐TENG under various compression ratios and stress conditions, highlighting its potential for real‐time monitoring in healthcare applications. [ABSTRACT FROM AUTHOR]

The distinctive layered configuration of δ-MnO2 renders it an exceptionally promising candidate as a cathode material for aqueous zinc-ion batteries (ZIBs). However, its practical utilization is constrained by the sluggish diffusion kinetics of Zn2+ and the capacity degradation resulting from lattice distortions occurring during charge and discharge cycles. To address these challenges, we have developed TMA–MnO2 by pre-intercalation of both tetramethylammonium ions (TMA+) and H2O molecules. The incorporation of TMA+ within the interlayer of δ-MnO2 results in the expansion of the interlayer spacing to 0.96 nm, thereby establishing a rapid diffusion pathway for Zn2+. At a rate of 0.2 A g−1, the ZIB employing TMA–MnO2 exhibits a specific capacity of 310.3 mA h g−1. Furthermore, after 1000 cycles at 2 A g−1, it maintains 91% of its initial capacity. Ex situ characterization techniques provide evidence of the co-intercalation mechanism of Zn2+/H+, concurrently indicating the stable presence of TMA+ as a structural support between layers during charge–discharge cycling. Density functional theory calculations provide evidence of the transformative impact of TMA+ introduction on the electron cloud density distribution within MnO2. This alteration leads to an enhancement in material conductivity and a substantial reduction in the diffusion barrier for Zn2+, consequently facilitating rapid diffusion kinetics. [ABSTRACT FROM AUTHOR]