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- ItemInterfacial Covalent Bonds Regulated Electron-Deficient 2D Black Phosphorus for Electrocatalytic Oxygen Reactions(Weinheim : Wiley-VCH, 2021) Wang, Xia; Raghupathy, Ramya Kormath Madam; Querebillo, Christine Joy; Liao, Zhongquan; Li, Dongqi; Lin, Kui; Hantusch, Martin; Sofer, Zdeněk; Li, Baohua; Zschech, Ehrenfried; Weidinger, Inez M.; Kühne, Thomas D.; Mirhosseini, Hossein; Yu, Minghao; Feng, XinliangDeveloping resource-abundant and sustainable metal-free bifunctional oxygen electrocatalysts is essential for the practical application of zinc–air batteries (ZABs). 2D black phosphorus (BP) with fully exposed atoms and active lone pair electrons can be promising for oxygen electrocatalysts, which, however, suffers from low catalytic activity and poor electrochemical stability. Herein, guided by density functional theory (DFT) calculations, an efficient metal-free electrocatalyst is demonstrated via covalently bonding BP nanosheets with graphitic carbon nitride (denoted BP-CN-c). The polarized P-N covalent bonds in BP-CN-c can efficiently regulate the electron transfer from BP to graphitic carbon nitride and significantly promote the OOH* adsorption on phosphorus atoms. Impressively, the oxygen evolution reaction performance of BP-CN-c (overpotential of 350 mV at 10 mA cm−2, 90% retention after 10 h operation) represents the state-of-the-art among the reported BP-based metal-free catalysts. Additionally, BP-CN-c exhibits a small half-wave overpotential of 390 mV for oxygen reduction reaction, representing the first bifunctional BP-based metal-free oxygen catalyst. Moreover, ZABs are assembled incorporating BP-CN-c cathodes, delivering a substantially higher peak power density (168.3 mW cm−2) than the Pt/C+RuO2-based ZABs (101.3 mW cm−2). The acquired insights into interfacial covalent bonds pave the way for the rational design of new and affordable metal-free catalysts. © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH
- ItemUltrathin two-dimensional conjugated metal– organic framework single-crystalline nanosheets enabled by surfactant-assisted synthesis(Cambridge : RSC, 2020) Wang, Zhonghao; Wang, Gang; Qi, Haoyuan; Wang, Mao; Wang, Mingchao; Park, SangWook; Wang, Huaping; Yu, Minghao; Kaiser, Ute; Fery, Andreas; Zhou, Shengqiang; Dong, Renhao; Feng, XinliangTwo-dimensional conjugated metal-organic frameworks (2D c-MOFs) have recently emerged for potential applications in (opto-)electronics, chemiresistive sensing, and energy storage and conversion, due to their excellent electrical conductivity, abundant active sites, and intrinsic porous structures. However, developing ultrathin 2D c-MOF nanosheets (NSs) for facile solution processing and integration into devices remains a great challenge, mostly due to unscalable synthesis, low yield, limited lateral size and low crystallinity. Here, we report a surfactant-assisted solution synthesis toward ultrathin 2D c-MOF NSs, including HHB-Cu (HHB = hexahydroxybenzene), HHB-Ni and HHTP-Cu (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene). For the first time, we achieve single-crystalline HHB-Cu(Ni) NSs featured with a thickness of 4-5 nm (∼8-10 layers) and a lateral size of 0.25-0.65 μm2, as well as single-crystalline HHTP-Cu NSs with a thickness of ∼5.1 ± 2.6 nm (∼10 layers) and a lateral size of 0.002-0.02 μm2. Benefiting from the ultrathin feature, the synthetic NSs allow fast ion diffusion and high utilization of active sites. As a proof of concept, when serving as a cathode material for Li-ion storage, HHB-Cu NSs deliver a remarkable rate capability (charge within 3 min) and long-term cycling stability (90% capacity retention after 1000 cycles), superior to the corresponding bulk materials and other reported MOF cathodes. This journal is © The Royal Society of Chemistry.
- ItemUltrathin positively charged electrode skin for durable anion-intercalation battery chemistries([London] : Nature Publishing Group UK, 2023) Sabaghi, Davood; Wang, Zhiyong; Bhauriyal, Preeti; Lu, Qiongqiong; Morag, Ahiud; Mikhailovia, Daria; Hashemi, Payam; Li, Dongqi; Neumann, Christof; Liao, Zhongquan; Dominic, Anna Maria; Nia, Ali Shaygan; Dong, Renhao; Zschech, Ehrenfried; Turchanin, Andrey; Heine, Thomas; Yu, Minghao; Feng, XinliangThe anion-intercalation chemistries of graphite have the potential to construct batteries with promising energy and power breakthroughs. Here, we report the use of an ultrathin, positively charged two-dimensional poly(pyridinium salt) membrane (C2DP) as the graphite electrode skin to overcome the critical durability problem. Large-area C2DP enables the conformal coating on the graphite electrode, remarkably alleviating the electrolyte. Meanwhile, the dense face-on oriented single crystals with ultrathin thickness and cationic backbones allow C2DP with high anion-transport capability and selectivity. Such desirable anion-transport properties of C2DP prevent the cation/solvent co-intercalation into the graphite electrode and suppress the consequent structure collapse. An impressive PF6−-intercalation durability is demonstrated for the C2DP-covered graphite electrode, with capacity retention of 92.8% after 1000 cycles at 1 C and Coulombic efficiencies of > 99%. The feasibility of constructing artificial ion-regulating electrode skins with precisely customized two-dimensional polymers offers viable means to promote problematic battery chemistries.
- ItemUltrathin positively charged electrode skin for durable anion-intercalation battery chemistries([London] : Nature Publishing Group UK, 2023) Sabaghi, Davood; Wang, Zhiyong; Bhauriyal, Preeti; Lu, Qiongqiong; Morag, Ahiud; Mikhailovia, Daria; Hashemi, Payam; Li, Dongqi; Neumann, Christof; Liao, Zhongquan; Dominic, Anna Maria; Nia, Ali Shaygan; Dong, Renhao; Zschech, Ehrenfried; Turchanin, Andrey; Heine, Thomas; Yu, Minghao; Feng, XinliangThe anion-intercalation chemistries of graphite have the potential to construct batteries with promising energy and power breakthroughs. Here, we report the use of an ultrathin, positively charged two-dimensional poly(pyridinium salt) membrane (C2DP) as the graphite electrode skin to overcome the critical durability problem. Large-area C2DP enables the conformal coating on the graphite electrode, remarkably alleviating the electrolyte. Meanwhile, the dense face-on oriented single crystals with ultrathin thickness and cationic backbones allow C2DP with high anion-transport capability and selectivity. Such desirable anion-transport properties of C2DP prevent the cation/solvent co-intercalation into the graphite electrode and suppress the consequent structure collapse. An impressive PF6−-intercalation durability is demonstrated for the C2DP-covered graphite electrode, with capacity retention of 92.8% after 1000 cycles at 1 C and Coulombic efficiencies of > 99%. The feasibility of constructing artificial ion-regulating electrode skins with precisely customized two-dimensional polymers offers viable means to promote problematic battery chemistries.
- ItemFreestanding MXene‐based macroforms for electrochemical energy storage applications(Hoboken, NJ : Wiley, 2023) Lu, Qiongqiong; Liu, Congcong; Zhao, Yirong; Pan, Wengao; Xie, Kun; Yue, Pengfei; Zhang, Guoshang; Omar, Ahmad; Liu, Lixiang; Yu, Minghao; Mikhailova, DariaFreestanding MXene-based macroforms have gained significant attention as versatile components in electrochemical energy storage applications owing to their interconnected conductive network, strong mechanical strength, and customizable surface chemistries derived from MXene nanosheets. This comprehensive review article encompasses key aspects related to the synthesis of MXene nanosheets, strategies for structure design and surface medication, surface modification, and the diverse fabrication methods employed to create freestanding MXene-based macroform architectures. The review also delves into the recent advancements in utilizing freestanding MXene macroforms for electrochemical energy storage applications, offering a detailed discussion on the significant progress achieved thus far. Notably, the correlation between the macroform's structural attributes and its performance characteristics is thoroughly explored, shedding light on the critical factors influencing efficiency and durability. Despite the remarkable development, the review also highlights the existing challenges and presents future perspectives for freestanding MXene-based macroforms in the realms of high-performance energy storage devices. By addressing these challenges and leveraging emerging opportunities, the potential of freestanding MXene-based macroforms can be harnessed to enable groundbreaking advancements in the field of energy storage.