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1. Surface Photon‐Engineered Infrared‐Black Metametal Enabled Enhancement of Heat Dissipation

   https://doi.org/10.1002/adfm.202205016  

   Tian, Yanpei; Liu, Xiaojie; Xie, Lijia; Xu, Shilin; Chen, Fangqi; Mu, Ying; Liu, Yang; Minus, Marilyn_L; Zheng, Yi (September 2022, Advanced Functional Materials)

   Abstract Heat dissipation is a severe barrier for ever‐smaller and more functionalized electronics, necessitating the continuous development of accessible, cost‐effective, and highly efficient cooling solutions. Metals, such as silver and copper, with high thermal conductivity, can efficiently remove heat. However, ultralow infrared thermal emittance (<0.03) severely restricts their radiative heat dissipation capability. Here, a solution‐processed chemical oxidation reaction is demonstrated for transfiguring “infrared‐white” metals (high infrared thermal reflectance) to “infrared‐black” metametals (high infrared thermal emittance). Enabled by strong molecular vibrations of metal‐oxygen chemical bonds, this strategy via assembling nanostructured metal oxide thin films on metal surface yields infrared spectrum manipulation, high and omnidirectional thermal emittance (0.94 from 0 to 60°) with excellent thermomechanical stability. The thin film of metal oxides with relatively high thermal conductivity does not hinder heat dissipation. “Infrared‐black” meta‐aluminum shows a temperature drop of 21.3 °C corresponding to a cooling efficiency of 17.2% enhancement than the pristine aluminum alloy under a heating power of 2418 W m⁻². This surface photon‐engineered strategy is compatible with other metals, such as copper and steel, and it broadens its implementation for accelerating heat dissipation. 

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2. In Situ Formation of Polymer-Inorganic Solid-Electrolyte Interphase for Stable Polymeric Solid-State Lithium Metal Batteries

   https://doi.org/10.1016/j.chempr.2021.06.019  

   Deng, Tao; Cao, Longsheng; He, Xinzi; Li, Ai-Min; Li, Dan; Xu, Jijian; Liu, Sufu; Bai, Panxing; Jin, Ting; Ma, Lin; et al (January 2021, Chem)

   null (Ed.)

   Composite polymer electrolytes (CPEs) for solid-state Li metal batteries (SSLBs) still suffer from gradually increased interface resistance and unconstrained Li dendrite growth. Herein, we addressed the challenges by designing a LiF-rich inorganic solid-electrolyte interphase (SEI) through introducing a fluoride-salt concentrated interlayer on CPE film. The rigid and flexible CPE helps accommodate the volume change of electrodes, while the polymeric high-concentrated electrolyte (PHCE) surface-layer regulates Li-ion flux due to the formation of a stable LiF-rich SEI via anion reduction. The designed CPE-PHCE presents enhanced ionic conductivity and high oxidation stability of > 5.0V (vs. Li/Li+). What’s more, it dramatically reduces the interfacial resistance and achieves a high critical current density of 4.5 mA cm-2 for dendrite-free cycling. The SSLBs, fabricated with thin CPE-PHCE membrane (< 100 μm) and Co-free LiNiO2 cathode, exhibit exceptional electrochemical performance and long cycling stability. This approach of SEI design can also be applied to other types of batteries. 

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3. Nanostructured core–shell metal borides–oxides as highly efficient electrocatalysts for photoelectrochemical water oxidation

   https://doi.org/10.1039/c9nr09818f  

   Lu, Can; Jothi, Palani R.; Thersleff, Thomas; Budnyak, Tetyana M.; Rokicinska, Anna; Yubuta, Kunio; Dronskowski, Richard; Kuśtrowski, Piotr; Fokwa, Boniface P.; Slabon, Adam (February 2020, Nanoscale)

   null (Ed.)

   Oxygen evolution reaction (OER) catalysts are critical components of photoanodes for photoelectrochemical (PEC) water oxidation. Herein, nanostructured metal boride MB (M = Co, Fe) electrocatalysts, which have been synthesized by a Sn/SnCl 2 redox assisted solid-state method, were integrated with WO 3 thin films to build heterojunction photoanodes. As-obtained MB modified WO 3 photoanodes exhibit enhanced charge carrier transport, amended separation of photogenerated electrons and holes, prolonged hole lifetime and increased charge carrier density. Surface modification of CoB and FeB significantly enhances the photocurrent density of WO 3 photoanodes from 0.53 to 0.83 and 0.85 mA cm −2 , respectively, in transient chronoamperometry (CA) at 1.23 V vs. RHE (V RHE ) under interrupted illumination in 0.1 M Na 2 SO 4 electrolyte (pH 7), corresponding to an increase of 1.6 relative to pristine WO 3 . In contrast, the pristine MB thin film electrodes do not produce noticeable photocurrent during water oxidation. The metal boride catalysts transform in situ to a core–shell structure with a metal boride core and a metal oxide (MO, M = Co, Fe) surface layer. When coupled to WO 3 thin films, the CoB@CoO x nanostructures exhibit a higher catalytic enhancement than corresponding pure cobalt borate (Co-B i ) and cobalt hydroxide (Co(OH) x ) electrocatalysts. Our results emphasize the role of the semiconductor–electrocatalyst interface for photoelectrodes and their high dependency on materials combination. 

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4. Thermoelectric properties of copper chalcogenide alloys deposited via the solution-phase using a thiol–amine solvent mixture

   https://doi.org/10.1039/c6ra15929j  

   Ma, Yuanyu; Vartak, Prathamesh B.; Nagaraj, Prajwal; Wang, Robert Y. (January 2016, RSC Advances)

   There has been a growing interest in solution-phase routes to thermoelectric materials due to the decreased costs and novel device architectures that these methods enable. Many excellent thermoelectric materials are metal chalcogenide semiconductors and the ability to create soluble metal chalcogenide semiconductor precursors using thiol–amine solvent mixtures was recently demonstrated by others. In this paper, we report the first thermoelectric property measurements on metal chalcogenide thin films made in this manner. We create Cu 2−x Se y S 1−y and Ag-doped Cu 2−x Se y S 1−y thin films and study the interrelationship between their composition and room temperature thermoelectric properties. We find that the precursor annealing temperature affects the metal : chalcogen ratio, and leads to charge carrier concentration changes that affect the Seebeck coefficient and electrical conductivity. Increasing the Se : S ratio increases electrical conductivity and decreases the Seebeck coefficient. We also find that incorporating Ag into the Cu 2−x Se y S 1−y film leads to appreciable improvements in thermoelectric performance by increasing the Seebeck coefficient and decreasing thermal conductivity. Overall, we find that the room temperature thermoelectric properties of these solution-processed materials are comparable to measurements on Cu 2−x Se alloys made via conventional thermoelectric material processing methods. Achieving parity between solution-phase processing and conventional processing is an important milestone and demonstrates the promise of this binary solvent approach as a solution-phase route to thermoelectric materials. 

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5. Lithium-activated SnS–graphene alternating nanolayers enable dendrite-free cycling of thin sodium metal anodes in carbonate electrolyte

   https://doi.org/10.1039/d0ee02423f  

   Liu, Wei; Chen, Zidong; Zhang, Zheng; Jiang, Pingxian; Chen, Yungui; Paek, Eunsu; Wang, Yixian; Mitlin, David (January 2021, Energy & Environmental Science)

   null (Ed.)

   Sodium metal battery (SMB, NMB) anodes can become dendritic due to an electrochemically unstable native Na-based solid electrolyte interphase (SEI). Herein Li-ion activated tin sulfide graphene nanocomposite membrane (A-SnS–G) is employed as an artificial SEI layer, allowing cyclability of record-thin 100 μm Na metal foils. The thin Na metal is prepared by a self-designed metallurgical rolling protocol. A-SnS–G is initially placed onto the polypropylene (PP) separator but becomes in situ transferred onto the Na metal surface. Symmetric metal cells protected by A-SnS–G achieve low-overpotential extended high-rate cycling in a standard carbonate electrolyte (EC : DEC = 1 : 1, 5% FEC). Accumulated capacity of 1000 mA h cm −2 is obtained after 500 cycles at 4 mA cm −2 , with accumulated capacity-to-foil capacity (A/F) ratio of 90.9. This is among the most favorable cycle life, accumulated capacity, and anode utilization combinations reported. Protection by non-activated SnS–G membrane yields significantly worse cycling, albeit still superior to the baseline unprotected sodium. Post-mortem and dedicated light optical analysis indicate that metal swelling, dendrite growth and dead metal formation is extensive for the unprotected sample, but is suppressed with A-SnS–G. Per XPS, post-100 cycles near-surface structure of A-SnS–G is rich in metallic Sn alloys and inorganic carbonate salts. Even after 300 cycles, Li-based SEI components ROCO 2 -Li, Li 2 CO 3 and LiF are detected with A-SnS–G. As a proof of principle, an SMB with a high mass loading (6 mg cm −2 ) NVP cathode and a A-SnS–G protected anode delivered extended cyclability, achieving 74 mA h g −1 after 400 cycles at 0.4C. 

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