Synergistic shallow impurity levels and multiscale defect engineering boost GeTe thermoelectric performance to ZT of 2.15
Peer-Reviewed Publication
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Severe parameter coupling between electrical and thermal transport limits the performance of GeTe-based thermoelectrics. A research team led by Prof. Lei Miao and Prof. Jie Gao successfully mitigated this trade-off through a synergistic Sb/Ni co-doping strategy. By leveraging Ni-induced shallow impurity levels to enhance carrier effective mass and forming in situ NiGe nanophases to suppress lattice thermal conductivity, the study optimized the interdependent transport properties. This approach yielded a peak figure of merit (ZT) of 2.15 and a single-leg device conversion efficiency of ~10%, demonstrating significant potential for mid-temperature waste heat recovery.
Zirconium carbide (ZrC) ceramics, essential for hypersonic vehicles and next-generation nuclear systems, are notoriously difficult to sinter and are inherently brittle. Researchers have now developed a novel two-step spark plasma sintering (SPS) process using TiSi2 and B4C additives to create a multi-scale microstructure. The resulting ZrC-based ceramic (ZTS-30B) achieves a remarkable flexural strength of 824 MPa and fracture toughness of 7.5 MPa·m¹/², significantly outperforming most ZrC-based ceramics by integrating atomic-scale solid solution strengthening, nano-scale SiC pinning, and micro-scale TiB₂-SiC agglomerates toughening.
A new self-rectifying memristor array with exceptional stability and precise multi-state regulation capabilities has been developed, laying a hardware foundation for efficient neuromorphic computing. When integrated with a simulated annealing algorithm, it achieves fast and accurate image restoration, showcasing promising application prospects.
The guest-host chemistry in polymer electrolytes plays a crucial role for all-solid-state Li metal batteries, where the stable operation of such batteries heavily relies on high ion conductivity, strong mechanical properties and stable interfaces of the electrolyte. While traditional ceramic fillers can boost ion conductivity, they fail to improve interfacial stability. In this study, we introduce intermolecular hydrogen bonding into a polyethylene oxide (PEO)-based polymer electrolyte through the incorporation of metal organic framework (MOF) and lithium nitrate additives. The hydrogen on the PEO chain is found to be tightly interacted with the oxygen nodes of UiO-66 MOF and nitrate anions, creating a cross-linked framework that reduces the crystallinity of the PEO and enhances the integrity of composite. This interaction induces a beneficial Li3N and LiF-rich solid electrolyte interphase, ensuring 2000 hours of stable lithium metal operation without short-circuits. The strong polysulfide adsorption enables compatibility with high-capacity sulfur cathodes, resulting in solid-state Li-S batteries that can achieve a high capacity of 913.8 mAh g-1 and exhibit stable cycling performance. This work demonstrates the deep understanding of guest-host chemistry in polymer electrolytes and their potential in developing energy-dense solid-state Li metal batteries.
High-voltage cathodes like spinel LiNi0.5Mn1.5O4 (LNMO) promise cheaper, more powerful electric vehicle batteries, but they degrade quickly with standard electrolytes. A research team has developed a novel all-fluorinated electrolyte (AFE) that forms a robust, fluorine-rich interphase on the cathode. This "protective armor" allows the battery to operate stably at high voltages (up to 4.9 V) and elevated temperatures, paving the way for high-energy-density lithium metal batteries.