The advanced lithium‐ion batteries that can tolerate zero‐volt storage (ZVS) are in high demand for implantable medical devices and spacecraft. However, ZVS can raise the anode potential, leading to ...Cu current collector dissolution and solid‐electrolyte interphase (SEI) degradation, especially at 37 °C. In this contribution, by quantitatively regulating the dosage of Li6CoO4 cathode additives, controllable potential of the working anode under abusive‐discharge conditions is demonstrated. The addition of Li6CoO4 keeps zero‐crossing potential (ZCP) and the potential of ZVS below 2.0 V (vs Li/Li+) for LiCoO2|mesocarbon microbead cells at 37 °C. The capacity retention ratio (CRR) increases from 69.1% and 35.9% to 98.6% and 90.8% after 10 and 20 days of ZVS, respectively. The Cu dissolution and SEI degradation are effectively suppressed, while the over‐lithiated cathode exhibits high reversible capacity after ZVS. The limiting conditions of long‐term ZVS are further explored and a corresponding guide map is designed. When quantitatively regulating ZCP and the potential in ZVS, Cu dissolution, SEI degradation, and irreversible conversion of the cathode constitute the limiting conditions. This contribution designs the most reasonable potential range for ZVS protection at 37 °C, and realizes the best CRR record through precise potential regulation for the first time.
The long‐term zero‐volt storage (ZVS) in lithium‐ion batteries (LIBs) at 37 °C is achieved through quantitative regulation of anode potential in working cells. This approach prevents Cu current collector dissolution and SEI degradation by controlling the Li6CoO4 content in cathode, with reversible capacity in slight over‐lithiation LCO demonstrated. This paves the way for emerging applications in active implantable medical devices.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Contact prelithiation is an important strategy to compensate the initial capacity loss of lithium‐ion batteries. However, the dead Li generated from inadequate Li conversion reduces the cycling ...stability of rechargeable batteries. Herein a mono‐solvent dimethyl carbonate (DMC) electrolyte was employed in contact prelithiation for the first time. We discover that the low‐organic‐content raw electrolyte interphase (REI) induced by this electrolyte on Li source and anode is a mixed ion/electron conductor. Therefore, electron channels can be maintained even when the Li source has been completely wrapped by the DMC‐derived REI. As a result, an outstanding Li source utilization of 92.8 % and a negligible dead Li yield can be realized. This strategy renders batteries with a very high initial Coulombic efficiency (90.0 %) and an excellent capacity retention (94.9 %) over 210 cycles, highlighting the significance of REI for effective contact prelithiation.
A raw mixed ion/electron conductor interphase is established on the Li source and anode by using a dimethyl carbonate electrolyte, enabling an unimpeded electron channel structure for elevating the Li source utilization and reducing the formation of dead Li.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The direct functionalization of C-H bonds has drawn the attention of chemists for almost a century. C-H activation has mainly been achieved through four metal-mediated pathways: oxidative addition, ...electrophilic substitution, σ-bond metathesis and metal-associated carbene/nitrene/oxo insertion. However, the identification of methods that do not require transition-metal catalysts is important because methods involving such catalysts are often expensive. Another advantage would be that the requirement to remove metallic impurities from products could be avoided, an important issue in the synthesis of pharmaceutical compounds. Here, we describe the identification of a cross-coupling between aryl iodides/bromides and the C-H bonds of arenes that is mediated solely by the presence of 1,10-phenanthroline as catalyst in the presence of KOt-Bu as a base. This apparently transition-metal-free process provides a new strategy with which to achieve direct C-H functionalization.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Perovskite photovoltaics are strong potential candidates to drive low‐power off‐grid electronics for indoor applications. Compared with rigid devices, flexible perovskite devices can provide a more ...suitable surface for indoor small electronic devices, enabling them have a broader indoor application prospect. However, the mechanical stability of flexible perovskite photovoltaics is an urgent issue solved. Herein, a kind of 3D crosslinking agent named borax is selected to carry out grain boundary penetration treatment on perovskite film to realize full‐dimensional stress release. This strategy improves the mechanical and phase stabilities of perovskite films subjected to external forces or large temperature changes. The fabricated perovskite photovoltaics deliver a champion power conversion efficiency (PCE) of 21.63% under AM 1.5G illumination, which is the highest one to date. The merit of low trap states under weak light makes the devices present a superior indoor PCE of 31.85% under 1062 lux (LED, 2956 K), which is currently the best flexible perovskite indoor photovoltaic device. This work provides a full‐dimensional grain boundary stress release strategy for highly stable flexible perovskite indoor photovoltaics.
A grain boundary stress release strategy is proposed for high‐stability flexible perovskite indoor photovoltaics by the grain boundary penetration with borax 3D stretchable molecules. The full‐dimensional grain boundary stress release enables the flexible perovskite photovoltaics deliver a champion power conversion efficiency (PCE) of 21.63% under AM 1.5G illumination and an indoor PCE of 31.85% under 1062 lux.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Halide perovskite films processed from solution at low‐temperature offer promising opportunities to make flexible solar cells. However, the brittleness of perovskite films is an issue for mechanical ...stability in flexible devices. Herein, photo‐crosslinked 6,6‐phenylC61‐butyric oxetane dendron ester (C‐PCBOD) is used to improve the mechanical stability of methylammonium lead iodide (MAPbI3) perovskite films. Also, it is demonstrated that C‐PCBOD passivates the grain boundaries, which reduces the formation of trap states and enhances the environmental stability of MAPbI3. Thus, MAPbI3 perovskite solar cells are prepared on solid and flexible substrates with record efficiencies of 20.4% and 18.1%, respectively, which are among the highest ever reported for MAPbI3 on both flexible and solid substrates. The result of this work provides a step improvement toward stable and efficient flexible perovskite solar cells.
Embracing perovskite grains in a soft fullerene network represents a new and scalable approach, to make perovskite mechanically stable and thus compatible with flexible substrates. The method is demonstrated to prepare flexible perovskite solar cells with the highest ever reported power conversion efficiency. The superior mechanical stability from device performance under working conditions is characterized in situ.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This research shows that spatial distance between visual representations of a product and consumers may enhance or devalue consumers’ perceptions of the brand depending on the brand image ...(prestigious vs. popular). The authors suggest that spatial distance signals prestige when status and luxury are relevant to the brand image, and decreased distance signals social closeness when popularity and broad appeal are relevant to the brand image. The authors show that for prestigious brands whose brand image is associated with status and luxury, consumers’ attitude toward the product becomes more favorable and their willingness to pay a premium for the product grows as the distance between the visual representations of the product and the consumer increases. In contrast, for popular brands whose brand image is associated with broad appeal and social connectedness, the closer the distance, the more favorable is consumers’ attitude and the higher their willingness to pay a premium. The findings provide useful guidelines to marketers on the use of visual cues in advertising and product displays.
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IZUM, KILJ, NUK, OILJ, PILJ, SAZU, UKNU, UL, UM, UPUK
The development of effective and stable hole transporting materials (HTMs) is very important for achieving high‐performance planar perovskite solar cells (PSCs). Herein, copper salts (cuprous ...thiocyanate (CuSCN) or cuprous iodide (CuI)) doped 2,2,7,7‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9‐spirobifluorene (spiro‐OMeTAD) based on a solution processing as the HTM in PSCs is demonstrated. The incorporation of CuSCN (or CuI) realizes a p‐type doping with efficient charge transfer complex, which results in improved film conductivity and hole mobility in spiro‐OMeTAD:CuSCN (or CuI) composite films. As a result, the PCE is largely improved from 14.82% to 18.02% due to obvious enhancements in the cell parameters of short‐circuit current density and fill factor. Besides the HTM role, the composite film can suppress the film aggregation and crystallization of spiro‐OMeTAD films with reduced pinholes and voids, which slows down the perovskite decomposition by avoiding the moisture infiltration to some extent. The finding in this work provides a simple method to improve the efficiency and stability of planar perovskite solar cells.
Copper salts (cuprous thiocyanate or cuprous iodide) doped 2,2,7,7‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9‐spirobifluorene is used as the hole transport layer in planar perovskite solar cells by their good film conductivity and hole mobility. As a result, a maximum 18.02% power conversion efficiency is achieved with improved cell stability. 2D grazing incidence X‐ray diffraction technique is utilized to probe the cell degradation process.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Photodynamic therapy (PDT) typically involves oxygen (O2) consumption and therefore suffers from greatly limited anticancer therapeutic efficacy in tumor hypoxia. Here, it is reported for the first ...time that amine‐terminated, PAMAM dendrimer‐encapsulated gold nanoclusters (AuNCs‐NH2) can produce O2 for PDT via their intrinsic catalase‐like activity. The AuNCs‐NH2 not only show optimum H2O2 consumption via the catalase‐like activity over the physiological pH range (i.e., pH 4.8–7.4), but also extend such activity to acidic conditions. The possible mechanism is deduced from that the enriched tertiary amines of dendrimers are easily protonated in acidic solutions to facilitate the preadsorption of OH on the metal surface, thereby favorably triggering the catalase‐like reaction. By taking advantage of the exciting feature on AuNCs‐NH2, the possibility to supply O2 via the catalase‐like activity of AuNCs‐NH2 for PDT against hypoxia of cancer cells was further studied. This proof‐of‐concept study provides a simple way to combine current O2‐dependent cancer therapy of PDT to overcome cancer cell hypoxia, thus achieving more effective anticancer treatments.
PAMAM dendrimer‐encapsulated gold nanoclusters (AuNCs‐NH2) exhibit their catalase‐like activity over a pH range relevant to biological microenvironments (i.e., pH 4.8–7.4), such that AuNCs‐NH2 can catalyze physiological hydrogen peroxide (H2O2) to produce O2 that self‐supplies for photodynamic therapy against hypoxic cancer cells.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Hepatocellular carcinoma (HCC) has become a leading cause of cancer-related death, making the elucidation of its underlying mechanisms an urgent priority. Inflammation is an adaptive response to ...infection and tissue injury under strict regulations. When the host regulatory machine runs out of control, nonresolving inflammation occurs. Nonresolving inflammation is a recognized hallmark of cancer that substantially contributes to the development and progression of HCC. The HCC-associated inflammation can be initiated and propagated by extrinsic pathways through activation of pattern-recognition receptors (PRRs) by pathogen-associated molecule patterns (PAMPs) derived from gut microflora or damage-associated molecule patterns (DAMPs) released from dying liver cells. The inflammation can also be orchestrated by the tumor itself through secreting factors that recruit inflammatory cells to the tumor favoring the buildup of a microenvironment. Accumulating datas from human and mouse models showed that inflammation promotes HCC development by promoting proliferative and survival signaling, inducing angiogenesis, evading immune surveillance, supporting cancer stem cells, activating invasion and metastasis as well as inducing genomic instability. Targeting inflammation may represent a promising avenue for the HCC treatment. Some inhibitors targeting inflammatory pathways have been developed and under different stages of clinical trials, and one (sorafenib) have been approved by FDA. However, as most of the data were obtained from animal models, and there is a big difference between human HCC and mouse HCC models, it is challenging on successful translation from bench to bedside.
Because of the high capacity of lithium (Li) metal and the intrinsic safety of solid-state electrolyte, solid-state Li-metal batteries are regarded as a promising candidate for next-generation energy ...storage. However, uncontrollable dendrite growth and large interfacial resistance severely hamper the practical applications. This review summarizes the issues generated by the marriage of Li-metal anodes and solid-state electrolytes. First, the current challenges are underscored. Specific attention is paid to the large interfacial resistance, uncontrolled dendrite growth, and low operation current or capacity. The second section is dedicated primarily to understanding the ionic channels in the composite electrolyte and the space charge layers in the interfacial region. Based on these dilemmas and working principles, emerging strategies to render solid-state Li-metal batteries are summarized. Finally, the general conclusion and perspective on the current limitations and recommended research of solid-state Li-metal batteries are presented.
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Li metal is extensively focused because of its ultra-high theoretical capacity (3,860 mAh g−1, 10 times higher than that of graphite) and the most negative electrochemical potential (−3.040 V versus standard hydrogen electrode). Relative to non-aqueous electrolyte, solid-state electrolyte exhibits enhanced safety. Therefore, the marriage of Li metal and solid-state electrolyte is expected to inherit the merits of both. However, the competitive solid-state Li-metal batteries encounter formidable challenges, including dendrite issues and poor solid-solid contact. Investigating the interdisciplinary issues of solid-state electrolyte and Li metal in integrated cells is necessary to realize efficient and safe solid-state Li-metal batteries. This review focuses on the energy chemistry issues generated from the marriage of Li metal and solid-state electrolyte instead of their respective problems. The current strategies, limitations, and emerging research directions are presented.
The marriage of Li-metal anodes and solid-state electrolytes is highly expected to achieve a battery with high energy density and enhanced safety. This review focuses on the energy chemistry generated from the marriage of Li-metal anodes and solid-state electrolytes, as well as the strategies and prospects to render efficient and safe solid-state Li-metal batteries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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