Evidence accumulated over the past decade shows that long non-coding RNAs (lncRNAs) are widely expressed and have key roles in gene regulation. Recent studies have begun to unravel how the biogenesis ...of lncRNAs is distinct from that of mRNAs and is linked with their specific subcellular localizations and functions. Depending on their localization and their specific interactions with DNA, RNA and proteins, lncRNAs can modulate chromatin function, regulate the assembly and function of membraneless nuclear bodies, alter the stability and translation of cytoplasmic mRNAs and interfere with signalling pathways. Many of these functions ultimately affect gene expression in diverse biological and physiopathological contexts, such as in neuronal disorders, immune responses and cancer. Tissue-specific and condition-specific expression patterns suggest that lncRNAs are potential biomarkers and provide a rationale to target them clinically. In this Review, we discuss the mechanisms of lncRNA biogenesis, localization and functions in transcriptional, post-transcriptional and other modes of gene regulation, and their potential therapeutic applications.
Sodium‐ion batteries have gained much attention for their potential application in large‐scale stationary energy storage due to the low cost and abundant sodium sources in the earth. However, the ...electrochemical performance of sodium‐ion full cells (SIFCs) suffers severely from the irreversible consumption of sodium ions of cathode during the solid electrolyte interphase (SEI) formation of hard carbon anode. Here, a high‐efficiency cathode sodiation compensation reagent, sodium oxalate (Na2C2O4), which possesses both a high theoretical capacity of 400 mA h g−1 and a capacity utilization as high as 99%, is proposed. The implementation of Na2C2O4 as sacrificial sodium species is successfully realized by decreasing its oxidation potential from 4.41 to 3.97 V through tuning conductive additives with different physicochemical features, and the corresponding mechanism of oxidation potential manipulation is analyzed. Electrochemical results show that in the full cell based on a hard carbon anode and a P2‐Na2/3Ni1/3Mn1/3Ti1/3O2 cathode with Na2C2O4 as a sodium reservoir to compensate for sodium loss during SEI formation, the capacity retention is increased from 63% to 85% after 200 cycles and the energy density is improved from 129.2 to 172.6 W h kg−1. This work can provide a new avenue for accelerating the development of SIFCs.
The development of sodium‐ion batteries has been hindered so far by the irreversible consumption of sodium ions of the cathode during the solid electrolyte interphase formation. Therefore, in search of a safe, cost‐effective, and highly efficient cathode sodiation reagent, the feasibility of Na2C2O4 as a sodium reservoir source for enhancing the performance of sodium‐ion batteries is investigated.
Abstract
Na-ion cathode materials operating at high voltage with a stable cycling behavior are needed to develop future high-energy Na-ion cells. However, the irreversible oxygen redox reaction at ...the high-voltage region in sodium layered cathode materials generates structural instability and poor capacity retention upon cycling. Here, we report a doping strategy by incorporating light-weight boron into the cathode active material lattice to decrease the irreversible oxygen oxidation at high voltages (i.e., >4.0 V vs. Na
+
/Na). The presence of covalent B–O bonds and the negative charges of the oxygen atoms ensures a robust ligand framework for the NaLi
1/9
Ni
2/9
Fe
2/9
Mn
4/9
O
2
cathode material while mitigating the excessive oxidation of oxygen for charge compensation and avoiding irreversible structural changes during cell operation. The B-doped cathode material promotes reversible transition metal redox reaction enabling a room-temperature capacity of 160.5 mAh g
−1
at 25 mA g
−1
and capacity retention of 82.8% after 200 cycles at 250 mA g
−1
. A 71.28 mAh single-coated lab-scale Na-ion pouch cell comprising a pre-sodiated hard carbon-based anode and B-doped cathode material is also reported as proof of concept.
As one of the fascinating high capacity cathodes, O3‐type layered oxides usually suffer from their intrinsic air sensitivity and sluggish kinetics originating from the spontaneous lattice Na ...extraction during air exposure and high tetrahedral site energy of Na+ diffusion transition state. What is worse, the improvement on the two handicaps is hard to simultaneously realize because of the contradiction between Na containment suggested in air stability mechanism and enhanced Na diffusion mentioned in kinetics strategy. Herein, it is shown that a simple strategy of introducing proper Na vacancies into lattice can simultaneously realize a dual performance improvement. Na vacancies decrease the charge density on transitional metal ions and enhance the antioxidative capability of material, ensuring a stable lattice Na containment for Na0.93Li0.12Ni0.25Fe0.15Mn0.48O2 when exposed to air. Additionally, more Na+ diffusional sites and enlarged Na layer spacing are obtained and result in a significantly decreased energy barrier from ≈1000 to 300 meV and a high rate capability of 70.8% retention at 2000 mA g−1. Remarkably, such a strategy can be easily realized by either pre‐ or post‐treating, which exhibits excellent universality for various O3 materials, implying its enormous potential to promote the commercial application of O3‐type cathodes.
A universal strategy of introducing proper Na vacancies into a crystal lattice is proposed to simultaneously improve air‐stability and kinetics of O3‐type layered oxide cathodes. The dual improvement benefits from the multiple effects of Na vacancies on crystalline and electronic structure, namely, decreased charge density on transition metal ions, enhanced antioxidative capability, decreased Na+ diffusion barrier, and optimized migration path.
The discovery of non-magnetic extreme magnetoresistance (XMR) materials has induced great interest because the XMR phenomenon challenges our understanding of how a magnetic field can alter electron ...transport in semimetals. Among XMR materials, the LaSb shows XMR and field-induced exotic behaviors but it seems to lack the essentials for these properties. Here, we study the magnetotransport properties and electronic structure of LaBi, isostructural to LaSb. LaBi exhibits large MR as in LaSb, which can be ascribed to the nearly compensated electron and hole with rather high mobilities. More importantly, our analysis suggests that the XMR as well as field-induced resistivity upturn and plateau observed in LaSb and LaBi can be well explained by the two-band model with the compensation situation. We present the critical conditions leading to these field-induced properties. It will contribute to the understanding of the XMR phenomenon and explore novel XMR materials.
Layered oxide cathodes usually exhibit high compositional diversity, thus providing controllable electrochemical performance for Na‐ion batteries. These abundant components lead to complicated ...structural chemistry, closely affecting the stacking preference, phase transition and Na+ kinetics. With this perspective, we explore the thermodynamically stable phase diagram of various P2/O3 composites based on a rational biphasic tailoring strategy. Then a specific P2/O3 composite is investigated and compared with its monophasic counterparts. A highly reversible structural evolution of P2/O3–P2/O3/P3–P2/P3–P2/Z/O3′–Z/O3′ based on the Ni2+/Ni3.5+, Fe3+/Fe4+ and Mn3.8+/Mn4+ redox couples upon sequential Na extraction/insertion is revealed. The reduced structural strain at the phase boundary alleviates the phase transition and decreases the lattice mismatch during cycling, endowing the biphasic electrode a large reversible capacity of 144 mAh g−1 with the energy density approaching 514 Wh kg−1.
A rational biphasic tailoring strategy to prepare layered composite cathodes with the desired phase ratio is proposed. Benefiting from the reversible phase transition within transition metal slabs and the decreased structure strain at the phase boundary of the intergrowth structure during Na extraction and insertion, the Com‐NaNMFT composite material demonstrates excellent electrochemical performance.
Chemical modification of electrode materials by heteroatom dopants is crucial for improving storage performance in rechargeable batteries. Electron configurations of different dopants significantly ...influence the chemical interactions inbetween and the chemical bonding with the host material, yet the underlying mechanism remains unclear. We revealed competitive doping chemistry of Group IIIA elements (boron and aluminum) taking nickel‐rich cathode materials as a model. A notable difference between the atomic radii of B and Al accounts for different spatial configurations of the hybridized orbital in bonding with lattice oxygen. Density functional theory calculations reveal, Al is preferentially bonded to oxygen and vice versa, and shows a much lower diffusion barrier than BIII. In the case of Al‐preoccupation, the bulk diffusion of BIII is hindered. In this way, a B‐rich surface and Al‐rich bulk is formed, which helps to synergistically stabilize the structural evolution and surface chemistry of the cathode.
A model study has been performed on Group IIIA element (boron and aluminum) co‐doped high‐nickel layered oxide cathode materials to understand competitive doping chemistry. A notable difference between the atomic radii of B and Al accounts for different spatial configurations of the hybridized orbital in bonding with lattice oxygen, resulting in the formation of a B‐rich surface and an Al‐rich bulk.
Using a panel of Chinese listed firms over the period 1998–2015, we examine the extent to which liquidity impacts firms' acquisition decisions, method of payment choice, and performance following ...mergers. We observe that cash-rich firms are more likely to attempt acquisitions, especially if they are subject to tunneling. Next, we find that bidders with higher growth opportunities are less likely to use cash payments in acquisitions. This effect is stronger for financially constrained bidders, who face greater opportunity costs of holding cash. Our last set of results highlights the under-performance of cash acquisitions in both the short and long term.
•We document the effect of liquidity on Chinese firms' acquisition decisions.•Tunneling is a motivation for cash-rich firms to make acquisitions.•Greater growth prospects reduce bidders' willingness to use cash payments.•This is true especially for financially constrained firms.•Cash acquisitions underperform stock acquisitions in both the short and long term.
Low‐cost and stable sodium‐layered oxides (such as P2‐ and O3‐phases) are suggested as highly promising cathode materials for Na‐ion batteries (NIBs). Biphasic hybridization, mainly involving P2/O3 ...and P2/P3 biphases, is typically used to boost their electrochemical performances. Herein, a P3/O3 intergrown layered oxide (Na2/3Ni1/3Mn1/3Ti1/3O2) as high‐rate and long‐life cathode for NIBs via tuning the amounts of Ti substitution in Na2/3Ni1/3Mn2/3−xTixO2 (x = 0, 1/6, 1/3, 2/3) is demonstrated. The X‐ray diffraction (XRD) Rietveld refinement and aberration‐corrected scanning transmission electron microscopy show the co‐existence of P3 and O3 phases, and density functional theory calculation corroborates the appearance of the anomalous O3 phase at the Ti substitution amount of 1/3. The P3/O3 biphasic cathode delivers an unexpected rate capability (≈88.7% of the initial capacity at a high rate of 5 C) and cycling stability (≈68.7% capacity retention after 2000 cycles at 1 C), superior to those of the sing phases P3‐Na2/3Ni1/3Mn2/3O2, P3‐Na2/3Ni1/3Mn1/2Ti1/6O2, and O3‐Na2/3Ni1/3Ti2/3O2. The highly reversible structural evolution of the P3/O3 integrated cathode observed by ex situ XRD, ex situ X‐ray absorption spectra, and the rapid Na+ diffusion kinetics, underpin the enhancement. These results show the important role of P3/O3 biphasic hybridization in designing and engineering layered oxide cathodes for NIBs.
P3/O3 biphasic Na2/3Ni1/3Mn1/3Ti1/3O2 cathode material is prepared for Na‐ion batteries by tuning the Ti amounts. This P3/O3 intergrown cathode delivers superior rate capability and cycling stability to those of the pristine P3 and O3 phases, which are underpinned by the observed highly reversible structural transition of P3/O3 biphase and the rapid Na+ diffusion kinetics.
Due to the obvious advantage in potassium reserves, potassium‐ion batteries (PIBs) are now receiving increasing research attention as an alternative energy storage system for lithium‐ion batteries ...(LIBs). Unfortunately, the large size of K+ makes it a challenging task to identify suitable electrode materials, particularly cathode ones that determine the energy density of PIBs, capable of tolerating the serious structural deformation during the continuous intercalation/deintercalation of K+. It is therefore of paramount importance that proper design principles of cathode materials be followed to ensure stable electrochemical performance if a practical application of PIBs is expected. Herein, the current knowledge on the structural engineering of cathode materials acquired during the battle against its performance degradation is summarized. The K+ storage behavior of different types of cathodes is discussed in detail and the structure–performance relationship of materials sensitive to their different lattice frameworks is highlighted. The key issues facing the future development of different categories of cathode materials are also highlighted and perspectives for potential approaches and strategies to promote the further development of PIBs are provided.
Potassium‐ion batteries (PIBs) are now receiving increasing research attention due to their obvious advantage regarding the potassium reserves. Cathode materials, which determine the energy density of PIBs, usually suffer from serious structural deformation during continuous K+ (de)intercalation. Therefore, proper structural‐design principles of cathode materials should be focused on to ensure high performance to promote the further development of PIBs.
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