Construction of Inorganic/Polymer Tandem Layer on Li Metal with Long-Term Stability by LiNO3 Concentration Gradient Electrolyte.

Metal electrode with long cycle life is decisive for the actual use of metal rechargeable batteries, while the dendrite growth and side reaction limit their cyclic stability. Herein, the construction of polymer and inorganic-rich SEI tandem layer structure on Li metal can be used for extraordinarily extending its cycle life is reported, which is generated by an in situ PVDF/LiF/LiNO3 (PLL) gel layer on the surface of Li metal with a chemically compatible ether solvent. The cycle life of Li//Li cells with the tandem layer structure is over 6000 h, six times longer than those with LiNO3 homogeneous electrolyte. It highlights the importance of LiNO3 concentration gradient electrolyte formed by the in situ PLL gel layer, in which highly concentrated LiNO3 is confined on the surface of Li metal to generate the uniform and inorganic-rich LiF/Li2 O/Li3 N layer on the bottom of PVDF/LiF with good mechanical strength, resulting in the dendrite free anode in cell cycling. The assembled Li//LiFePO4 and Li//NMC811 batteries show the capacity retention rate of 80.9% after 800 cycles and 82.3% after 500 cycles, respectively, much higher than those of references.

Multiple phonological activation in writing: evidence for cascadedness in Chinese written verb production.

The dynamics of information transmission through the lexical system during written word production remain underspecified. Existing studies largely come from noun production, relatively less work has explored verb production. Verbs, representing actions or states, are considered more abstract and are found to be more challenging to be produced. The present study investigated phonological involvement and the principles governing information flow during Chinese written verb production. Participants wrote down single verbs and verb phrases while ignoring phonologically related, or unrelated distractor pictures. Results revealed phonological facilitation effects on writing latencies from phonologically related distractors in the verb phrase generation. Findings provide novel chronometric evidence that information transmission during written production involves cascaded activation allowing multiple phonological codes to be activated prior to written output. This phonological facilitation effect signifies the influence of phonology, especially lexical phonology, has been underestimated in writing.

Uniform Nanoscale Ion-Selective Membrane Prepared by Precision Control of Solution Spreading and Evaporation.

Ion-selective membrane has broad application in various fields, while the present solution-processed techniques can only prepare uniform membrane with microscale thickness. Herein, a high-quality polymer membrane with nanoscale thickness and uniformity is precisely prepared by controlling solution spreading and solvent evaporation stability/rate. With the arrayed capillaries, the stable spreading of polymer solution with volume of microliter induces the formation of solution film with micrometers thickness. Moreover, the fast increase of solution dynamic viscosity during solvent evaporation inhibits nonuniform Marangoni flow and capillary flow in solution film. Consequently, the uniform Nafion-Li membranes with ∼200 nm thickness are prepared, while their Li+ conductivity is 2 orders of magnitude higher than that of commercially Nafion-117 membrane. Taking lithium-sulfur battery as a model device, the cells (capacities of 8-10 mAh cm-2) can stably operate for 150 cycles at a S loading of 12 mg cm-2 and an electrolyte/sulfur ratio of ∼7.

Accelerating S↔Li2 S Reactions in Li-S Batteries through Activation of S/Li2 S with a Bifunctional Semiquinone Catalyst.

The reaction rate bottleneck during interconversion between insulating S8 (S) and Li2 S fundamentally leads to incomplete conversion and restricted lifespan of Li-S battery, especially under high S loading and lean electrolyte conditions. Herein, we demonstrate a new catalytic chemistry: soluble semiquinone, 2-tertbutyl-semianthraquinone lithium (Li+ TBAQ⋅- ), as both e- /Li+ donor and acceptor for simultaneous S reduction and Li2 S oxidation. The efficient activation of S and Li2 S by Li+ TBAQ⋅- in the initial discharging/charging state maximizes the amount of soluble lithium polysulfide, thereby substantially improve the rate of solid-liquid-solid reaction by promoting long-range electron transfer. With in situ Raman spectra and theoretical calculations, we reveal that the activation of S/Li2 S is the rate-limiting step for effective S utilization under high S loading and low E/S ratio. Beyond that, the S activation ratio is firstly proposed as an accurate indicator to quantitatively evaluate the reaction rate. As a result, the Li-S batteries with Li+ TBAQ⋅- deliver superior cycling performance and over 5 times higher S utilization ratio at high S loading of 7.0 mg cm-2 and a current rate of 1 C compared to those without Li+ TBAQ⋅- . We hope this study contributes to the fundamental understanding of S redox chemical and inspires the design of efficient catalysis for advanced Li-S batteries.

A Multifunctional Silicon-Doped Polyether Network for Double Stable Interfaces in Quasi-Solid-State Lithium Metal Batteries.

Polymer-based quasi-solid-state electrolyte (QSE) is an effective means to solve the safety problem of lithium (Li) metal batteries, and stable solid-electrolyte-interface (SEI) layers between electrolyte and anode/cathode are highly required for their long-term stability. Herein, it is demonstrated that a silicon-doped polyether functions as a multifunctional unit, which can induce the formation of stable and robust SEI layers with rich Lix SiOy on both the surfaces of cathode and anode. It simultaneously solves the compatibility of electrolyte and electrodes in the quasi-solid-state Li-metal battery. Moreover, the robust polymer skeleton with a cross-linked network is beneficial to inhibit liquid volatilization and improve battery safety. The assembled Li|QSE|LiFePO4 batteries show a capacity retention rate as high as 97.5% after 400 cycles at 1 C (30 °C), and reach 78.1% after 1000 cycles. Furthermore, there is almost no attenuation of reversible capacity after 100 cycles for the assembled Li|QSE|LiNi0.8 Mn0.1 Co0.1 O2 batteries. The concept of silicon-doped polymer with a crosslinking structure provides an important strategy for designing solid-state or quasi-solid-state polymer electrolytes for the stable long-term operation of both anode and cathode.

In situ Construction of Robust Biphasic Surface Layers on Lithium Metal for Lithium-Sulfide Batteries with Long Cycle Life.

Lithium-sulfur (Li-S) batteries have potential in high energy density battery systems. However, intermediates of lithium polysulfides (LiPSs) can easily shuttle to the Li anode and react with Li metal to deplete the active materials and cause rapid failure of the battery. A facile solution pretreatment method for Li anodes involving a solution of metal fluorides/dimethylsulfoxide was developed to construct robust biphasic surface layers (BSLs) in situ. The BSLs consist of lithiophilic alloy (Lix M) and LiF phases on Li metal, which inhibit the shuttle effect and increase the cycle life of Li-S batteries. The BSLs allow Li+ transport and they inhibit dendrite growth and shield the Li anodes from corrosive reaction with LiPSs. Li-S batteries containing BSLs-Li anodes demonstrate excellent cycling over 1000 cycles at 1 C and simultaneously maintain a high coulombic efficiency of 98.2 %. Based on our experimental and theoretical results, we propose a strategy for inhibition of the shuttle effect that produces high stability Li-S batteries.

Separation of Metal-N4 Units in Metal-Organic Framework for Preparation of M-Nx/C Catalyst with Dense Metal Sites.

Metal and nitrogen codoped carbon (M-Nx/C) materials with good metal dispersion in a carbon matrix have attracted great attention because they can efficiently catalyze various kinds of chemical/electrochemical reactions. However, the existing strategies for preparing M-Nx/C materials still face the challenge of metal site aggregation when the carbon skeleton in the precursor is substantially lost during pyrolysis. Herein, we propose a general strategy that the increase of metal site density and inhibition of metal aggregation could be realized by separating M-N4 units in metal-organic frameworks (MOFs). The metal sites can be well separated and distributed in carbon materials during the pyrolysis of a metal-coordinated block copolymer, one of the specific MOFs. The strategy can be widely applicable for the synthesis of M-Nx/C materials with dense metal sites, such as Fe-, Mn-, Ni-, and Co-Nx/C materials, which are potentially used as the efficient catalysts for various kinds of reactions. Taking Fe-Nx/C as a model oxygen reduction reaction (ORR) electrocatalyst, it shows the ORR half-wave potentials of 0.90 and 0.81 V vs RHE in alkaline and acidic electrolytes, respectively.

Functional MYB transcription factor encoding gene AN2 is associated with anthocyanin biosynthesis in Lycium ruthenicum Murray.

BACKGROUND: Lycium ruthenicum Murray is an important economic plant in China and contains higher levels of anthocyanins in its fruits than other Lyciums. However, the genetic mechanism of anthocyanin production in this plant is unknown. RESULTS: Based on previous transcriptome analysis, LrAN2 and LbAN2, encoding MYB transcription factors, were isolated from L. ruthenicum and L. barbarum, respectively. Both genes contained two introns, encoded 257 amino acids with two-Aa difference, and carried the unabridged HTH-MYB, MYB-like DNA-binding, and SANT domains. In the phylogenetic trees, LrAN2 and LbAN2 were found to be closely related to NtAN2, which regulates anthocyanin biosynthesis in tobacco. Overexpression of LrAN2 and LbAN2 induced anthocyanin biosynthesis in all tissues of tobacco. The anthocyanin content in the leaves of transgenic lines with LbAN2 was lower than LrAN2. It indicated that the function of LbAN2 was weaker than LrAN2. The AN2 transcript could be detected only in the fruits of L. ruthenicum and increased during fruit development, accompanied by anthocyanin accumulation. In natural population, the alleles LrAN2 and LrAN2 were associated strictly with L. ruthenicum and L. barbarum, respectively. Moreover, an AN2 genetic diversity study suggested that Lyciums with yellow, white, purple, and jujube red fruits were derived from L. ruthenicum. CONCLUSIONS: Two AN2 alleles, from L. ruthenicum and L. barbarum, were functional MYB transcriptor regulating anthocyanin biosynthesis. The functional diversity and high expression level of LrAN2 could be the reason for high anthocyanin content in the fruit of L. ruthenicum. Lyciums with yellow, white, purple, and jujube red fruits were derived from L. ruthenicum based on AN2 sequence diversity. The results may be advantageous in identifying new varieties and breeding new cultivars.

It Is Not Necessary to Retrieve the Phonological Nodes of Context Objects for Chinese Speakers.

The issue of how activation is transmitted from semantic to phonological level in spoken production remains controversial. Recent evidences from alphabetic languages support a cascaded view. However, given the different architecture of phonological encoding in non-alphabetic languages, it is not clear whether this view applies in Chinese, as a non-alphabetic script. We therefore investigated whether the not-to-be named pictures activate their phonological properties in Chinese speech production. In Experiment 1, participants were presented a target English word and a context picture (semantically related or unrelated, phonologically related or unrelated to target word in Chinese) and were asked to translate the English word into a Chinese word. The translation latencies were faster in the semantically related condition than in the unrelated condition. By contrast, no difference between phonologically related and unrelated was observed. In Experiment 2, in order to promote participants phonological sensitivity in a word-translation task, we increased the proportion of phonologically related trials from 25 to 50%. In Experiment 3, we employed a word association task that was more sensitive to phonological activation of context objects than a word translation task. The phonological activation of context objects were absent again in Experiments 2 and 3. Bayes Factor analysis suggested that the absence of phonological activation of context pictures was reliable. Results consistently revealed that only target lemma could activate the corresponding phonological node to guide articulation whereas no phonological activation of non-target lemma's in Chinese. The present findings thus support a discrete model in Chinese spoken word production, which was contrastive with the cascaded view in alphabetic languages production.

Additivity of semantic and phonological effects: Evidence from speech production in Mandarin.

A number of previous studies using picture-word interference (PWI) tasks conducted with speakers of Western languages have demonstrated non-additive effects of semantic and form overlap between pictures and words, which may indicate underlying non-discrete processing stages in lexical retrieval. The present study used Mandarin speakers and presented Chinese characters as distractors. In two experiments, we crossed semantic relatedness with "pure" phonological (i.e., orthographically unrelated) relatedness and found statistically additive effects. In a third experiment, semantic relatedness was crossed with orthographic overlap (phonological overlap was avoided), and once again we found an additive pattern. The results are discussed with regard to possible cross-linguistic differences between Western and non-Western languages in terms of phonological encoding, as well as concerning the locus of relatedness effects in PWI tasks.

Seriality of semantic and phonological processes during overt speech in Mandarin as revealed by event-related brain potentials.

How is information transmitted across semantic and phonological levels in spoken word production? Recent evidence from speakers of Western languages such as English and Dutch suggests non-discrete transmission, but it is not clear whether this view can be generalized to other languages such as Mandarin, given potential differences in phonological encoding across languages. The present study used Mandarin speakers and combined a behavioral picture-word interference task with event-related potentials. The design factorially crossed semantic and phonological relatedness. Results showed semantic and phonological effects both in behavioral and electrophysiological measurements, with statistical additivity in latencies, and discrete time signatures (250-450 ms and 450-600 ms after picture onset for the semantic and phonological condition, respectively). Overall, results suggest that in Mandarin spoken production, information is transmitted from semantic to phonological levels in a sequential fashion. Hence, temporal signatures associated with spoken word production might differ depending on target language.

The temporal and spatial features of segmental and suprasegmental encoding during implicit picture naming: an event-related potential study.

This study investigated the temporal and spatial features of segmental and suprasegmental encoding within a syllable in Chinese speech production using an internal monitoring task. Native Chinese speakers viewed a series of pictures and made go/nogo decisions along dimensions of initial consonant, central vowel, or tone information of picture names. Behavioral data and the N200 indicated that initial consonant information is available about 20-80 ms earlier than central vowel or tone information, whereas vowel and tone occur concurrently within a syllable during implicit picture naming. Moreover, source analyses (using sLORETA) indicated that initial consonant, tone and vowel encoding all resulted in predominantly left hemispheric but relatively dissociative neural brain activation. These findings indicated that segmental (consonants and vowels) and suprasegmental (tones) encoding proceeds in an incremental manner, and both run in parallel and independently in speech production in agreement with WEAVER++.

Phonology contributes to writing: evidence from written word production in a nonalphabetic script.

Is the production of written words affected by their phonological properties? Most researchers agree that orthographic codes can be accessed directly from meaning, but the contribution of phonological codes to written word production remains controversial, mainly because studies have focused on languages with alphabetic scripts, and it is difficult to dissociate sound from spelling in such languages. We report results from a picture-word interference task in which Chinese participants wrote the names of pictures while attempting to ignore written distractor words. On some trials, the distractors were phonologically and orthographically related to the picture names; on other trials, the distractors were only phonologically related to the picture names; and on still other trials, the distractors and picture names were unrelated. Priming effects were found for both types of related distractors relative to unrelated distractors. This result constitutes clear evidence that phonological properties constrain orthographic output. Additionally, the results speak to the nature of Chinese orthography, suggesting subsemantic correspondences between sound and spelling.