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Solid state lithium metal batteries using garnet solid electrolytes such as LLZTO (Li6.4La3Zr1.5Ta0.5O12) promise substantial improvements in energy density and safety. However, practical implementation is hindered by lithium dendrite penetration at high current densities. Recent work shows that internal electrochemically induced mechanical stresses are large enough to propagate lithium dendrites and subsequently fracture solid electrolytes. This study builds on this understanding and demonstrates that stress‐driven dendrite propagation can be controlled via deflection at weakly bonded internal interfaces. This approach, based on a fracture‐mechanics analysis of multilayered composites, is investigated with a variety of interlayer materials that are embedded into LLZTO. The viability and effectiveness of dendrite deflection are most clearly evident with reduced graphene oxide where the critical current density increased from 0.6 to 3.8 mA cm−2. In this material, both the weak interface with LLZTO and the mixed ionic–electronic conducting nature of the interlayer appear to contribute to the improved performance. Additional insight into the mechanics of multilayered electrolytes is also obtained with finite element modeling. The overall results present a promising proof‐of‐concept demonstration along with important generalized design guidelines for creating multilayered solid electrolyte architectures that can enable high‐performance solid‐state batteries. [ABSTRACT FROM AUTHOR]

Phosphor‐converted laser lighting confronts enormous challenges in the development of color converters with high luminescence saturation owing to the thermal issues from laser irradiation and phosphor conversion. Herein, a high luminescence saturation Y3Al5O12: Ce3+‐diamond (YAG‐diamond) composite color converter by introducing diamond particles in phosphor‐in‐glass film (PiGF) coated on transparent sapphire substrate is proposed for high‐brightness laser‐driven white lighting. By optimizing the diamond content to 6 wt.%, the YAG‐diamond converter shows a thermal conductivity (TC) of 14.7 W·m−1·K−1 and displays higher luminescence intensity at 175 °C (1.15 times that at 25 °C). Under laser excitation, the YAG‐diamond converter achieves a luminous flux (LF) of 1990 lm at the laser power density (LPD) saturation threshold (ST) of 24.82 W·mm−2, which is far better than the PiGF@sapphire converter with a LF of 1364 lm@17.64 W·mm−2. The laser‐driven converter yields stable white laser light with a correlated color temperature (CCT) of 5714 K and a chromaticity coordinate of (0.3278, 0.3372) at the ST of 24.82 W·mm−2. Furthermore, the working temperature of the converter is decreased by 59 °C (26.6%) under LPD of 10.89 W·mm−2. These results indicate that the proposed YAG‐diamond composite converter displays excellent opto‐thermal performances, which may be a promising luminescence material in high‐brightness white laser lighting. [ABSTRACT FROM AUTHOR]

Phosphors-in-glass films (PiGFs) with thermally conductive substrates are considered to be an efficient color inorganic color conversion material for laser lighting. However, due to the contradiction between the light extraction and heat dissipation, achieving high brightness and excellent color quality simultaneously is still a big challenge. Herein, a unique architecture of bicolor PiGF with highly reflective interface design was proposed for high-quality laser lighting. The TiO 2 -glass films with different thicknesses were prepared on highly heat-conducting AlN substrates to obtain the TiO 2 –AlN (TA) substrates with various reflectance. In addition, mixed green/red, stacked green-red, and stacked red-green phosphor glass films were printed and sintered on the TA substrates to prepared three bicolor PiGF converters of M-PiTA, G-R-PiTA, and R-G-PiTA. At the TiO 2 -glass film thickness of 100 μm, the M-PiTA enables a luminous flux of 2053 lm@24.8 W/mm2, which is 1.9 times that of traditional M-PiGF-AlN converter (1077 lm@17.6 W/mm2). The M-PiTA converter realizes a high-quality white light with a CRI of 82.7 and a chromaticity coordinate of (0.3378, 0.3297). Furthermore, the M-PiTA converter enables higher luminance and light quality compared with the stacked G-R-PiTA and R-G-PiTA converters. With the laser power of 4.2 W, the working temperature of M-PiTA converter is only 59.2 °C, while that of R-G-PiTA and G-R-PiTA converters rises to 499 °C and 301 °C. The results demonstrate that the bicolor PiTA converters have broad prospects in the application of laser lighting. [ABSTRACT FROM AUTHOR]

Huge heat energy is ultimately generated in the color converter as a result of the nonradiative recombination of high‐power laser excitation. Inspired by the thermoelectric conversion, a high‐performance phosphor‐in‐glass film (PIGF) coated on a thermoelectric generator (TEG) for nonradiative energy recycling in high‐brightness laser lighting is proposed. The heat‐resistance PIGF with high luminescence is tightly coated on the hot‐side ceramic of TEG, while yielding a bright white light and promoting the heat conduction between PIGF and TEG. At the PIGF thickness of 60 µm, the PIGF‐TEG enables a natural white light with a luminous flux of 464 lm, a luminous efficacy of 194 lm W−1, a correlated color temperature (CCT) of 6552 K, and an appropriate chromaticity coordinate of (0.3117, 0.3302) under a laser power of 2.39 W. Aside from the high‐brightness output white light with a luminous flux of 1045 lm, the laser‐driven PIGF‐TEG produces the output voltage and current of 0.46 V and 174 mA under a laser power of 5.61 W, respectively. Therefore, the proposed PIGF‐TEG provides a potential strategy for heat energy recycling in high‐power phosphor‐converted lighting. [ABSTRACT FROM AUTHOR]

Next‐generation high‐brightness laser lighting confronts a key challenge in preparing static color‐converting materials with remarkable luminescence saturation. Herein, a novel architecture of transmissive Y3Al5O12: Ce3+ (YAG) phosphor‐in‐glass film (PiGF) with double‐sided sapphires, i.e., a sandwich structured sapphire@PiGF@sapphire (S@PiGF@S) composite, is designed and fabricated by a thermocompression sintering technology. This kind of material can tolerate high laser power density (LPD) for the efficient double‐sided thermal channels and the high‐energy laser spot away from the PiGF emitting layer. As a consequence, the optimized S@PiGF@S color converter yields white light with a high luminous flux (LF) of 7602 lm at a record luminescence saturation threshold of 46.47 W·mm−2 benefiting from its low working temperature of merely 284 °C, which is 6.3 times that of traditional PiGF@sapphire color converter (1205 lm@10.89 W·mm−2). These findings verify that the developed S@PiGF@S color converter enables preferably optical‐thermal performances for promising applications in high‐brightness laser lighting. [ABSTRACT FROM AUTHOR]