4 ) 3 (LATP) solid electrolyte is inexpensive, light, and highly ionically conductive but unstable against Li metal. To avoid the side reactions between LATP and Li metal, chemically inert and mechanically robust BN nanocoating was deposited onto LATP solid electrolyte as a stable interface to enable stable cycling in Li-metal batteries. This strategy can be applied to various unstable solid electrolytes and extend lifetime of solid-state Li-metal batteries with high energy density.

Solar reflective and thermally emissive surfaces offer a sustainable way to cool objects under sunlight. However, white or silvery reflectance of these surfaces does not satisfy the need for color. Here, we present a paintable bilayer coating that simultaneously achieves color and radiative cooling. The bilayer comprises a thin, visible-absorptive layer atop a nonabsorptive, solar-scattering underlayer. The top layer absorbs appropriate visible wavelengths to show specific colors, while the underlayer maximizes the reflection of near-to-short wavelength infrared (NSWIR) light to reduce solar heating. Consequently, the bilayer attains higher NSWIR reflectance (by 0.1 to 0.51) compared with commercial paint monolayers of the same color and stays cooler by as much as 3.0° to 15.6°C under strong sunlight. High NSWIR reflectance of 0.89 is realized in the blue bilayer. The performances show that the bilayer paint design can achieve both color and efficient radiative cooling in a simple, inexpensive, and scalable manner.

Solid-state lithium metal batteries with solid electrolytes are promising for next-generation energy-storage devices. However, it remains challenging to develop solid electrolytes that are both mechanically robust and strong against external mechanical load, due to the brittleness of ceramic electrolytes and the softness of polymer electrolytes. Herein, we propose a nacre-inspired design of ceramic/polymer solid composite electrolytes with the "brick-and-mortar" microstructure. The nacre-like ceramic/polymer electrolyte (NCPE) simultaneously possesses a much higher fracture strain (1.1%) than pure ceramic electrolytes (0.13%) and a much larger ultimate flexural strength (7.8 GPa) than pure polymer electrolytes (20 MPa). The electrochemical performance of NCPE is also much better than pure ceramic or polymer electrolytes, especially under mechanical load. A 5 × 5 cm 2 pouch cell with LAGP/poly(ether−acrylate) (PEA) NCPE exhibits stable cycling with a capacity retention of 95.6% over 100 cycles at room temperature, even undergoes a large This article is protected by copyright. All rights reserved. point load of 10 N. In contrast, cells based on pure ceramic and pure polymer electrolyte show poor cycle life. The NCPE provides a new design for solid composite electrolyte and opens up new possibilities for future solid-state lithium metal batteries and structural energy storage. The rapid-growing demands for portable electronics and electric vehicles have bolstered needs for next-generation lithium batteries with high energy density [1-4]. However, lithium batteries become more thermally vulnerable as energy density increases. Thermal runaway and explosion are prone to be triggered by failures such as mechanical damage and lithium dendrite growth inside batteries [5, 6]. Nonflammable solid-state ceramic electrolytes (SSEs) provide alternatives to conventional flammable liquid electrolytes [7-9]. Various ceramic electrolytes with attractive ionic conductivities have been developed in the past two decades, including NASICON-type Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 (LAGP) [10] , Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) [11, 12] , garnet Li 7 La 3 Zr 2 O 12 (LLZO) [13, 14] , and sulfides, such as This article is protected by copyright. All rights reserved. NCPEs, polymer electrolytes and ceramic electrolytes were cut with a thickness of 500 μm and a size of 1.5 cm. A loading rate of 0.5 mm min-1 and a support span of 1.5 cm were used in all tests. The results were averaged from those in five similar specimens. The flexural stress is and The flexural strain is , where F, L, w, h, and D are the applied point force, span length, sample width, thickness, and flexural deflection, respectively. Vickers indentation was carried out on SANS-UTM 6000 using a Vickers indenter. Finite Element Mechanical Simulation: 2D nonlinear finite element simulations were conducted using the software ABAQUS v6.14. In these simulations, the stress/strain distributions and crack propagation in a regular brick-mortar structure and a ceramic film are calculate...