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The high‐cost and limited availability of raw materials for lithium‐ion batteries hinder their future development and urge researchers to explore alternative battery systems. Among them, batteries utilizing the electrochemical redox reaction of metals such as Cu, Fe, Sn, etc. as the cathode to reversibly store and release energy are attractive because their raw materials are common and abundant. This review examines this type of novel battery system, introduces its basic mechanism and problems, analyses the strategies that are used to improve its reversibility and cycling stability and also proposes some possible future directions of investigations. [ABSTRACT FROM AUTHOR]

Dual‐ion battery (DIB) is a promising energy storage system because it can provide high power. However, the stability and rate performance of the battery depend strongly on the type of salt and solvents in the electrolyte. Herein, the use of lithium bis(fluorosulfonyl)imide (LiFSI) is studied, which has better high‐temperature stability, as salt in the DIB and develop a 3 m LiFSI fluoroethylene carbonate/methyl 2,2,2‐trifluoroethyl carbonate (FEC/FEMC) = 3:7 electrolyte, which stabilizes graphite–lithium DIB with 94.1% capacity retention after 2000 cycles at 5C. The DIB also exhibits excellent rate performance with 100.4 mAh g−1 capacity at 30C, with a utilization of 96.3% compared to capacity at 2C. The outstanding electrochemical performance is attributed to the thin cathode electrolyte interface (CEI) layer and fast FSI− transport kinetics, confirmed by X‐ray photoelectron spectroscopy and activation energy calculation. Superior cycle and rate performances are also obtained from a graphite–graphite full cell. Though, increasing salt concentration to 5 and 6 m leads to sluggish FSI− de‐intercalation reaction and lower capacity, which is attributed to solvent co‐intercalation. The research suggests that the electrolyte plays an important role in ion transport, surface film formation, and stability of DIB. [ABSTRACT FROM AUTHOR]

Metal–metal battery bears great potential for next‐generation large‐scale energy storage system because of its simple manufacture process and low production cost. However, the cross‐over of metal cations from the cathode to the anode causes a loss in capacity and influences battery stability. Herein, a coating of poly (ionic liquid) (PIL) with poly(diallyldimethylammonium bis(trifluoromethanesulfonyl)imide) (PDADMA+TFSI−) on a commercial polypropylene (PP) separator serves as an anion exchange membrane for a 3.3 V copper–lithium battery. The PIL has a positively charged polymer backbone that can block the migration of copper ions, thus improving Coulombic efficiency, long‐term cycling stability and inhibiting self‐discharge of the battery. It can also facilitate the conduction of anions through the membrane and reduce polarization, especially for fast charging/discharging. Bruce‐Vincent method gives the transport number in the electrolyte to be 0.25 and 0.04 for PP separator without and with PIL coating, respectively. This suggests that the PIL layer reduces the contribution of the internal current due to cation transport. The use of PIL as a coating layer for commercial PP separator is a cost‐effective way to improve overall electrochemical performance of copper–lithium batteries. Compared to PP and polyacrylic acid(PAA)/PP separators, the PIL/PP membrane raises the Coulombic efficiency to 99% and decreases the average discharge voltage drop to about 0.09 V when the current density is increased from 0.1 to 1 mA cm−2. [ABSTRACT FROM AUTHOR]

Air‐stable layered structured cathodes with high voltage and good cycling stability are highly desired for the practical application of Na‐ion batteries. Herein, we report a P2‐Na2/3Ni2/3Te1/3O2 cathode that is stable in ambient air with an average operating voltage of ~3.8 V, demonstrating excellent cycling stability with a capacity retention of more than 92.7% after 500 cycles at 20 mA g−1 and good rate capability with 91.9% capacity utilization at 500 mA g−1 with respect to capacity at 5 mA g−1 between 2.0 and 4.0 V. When the upper cutoff voltage is increased to 4.4 V, P2‐Na2/3Ni2/3Te1/3O2 delivers a reversible capacity of 71.9 mAh g−1 and retains 91.8% of the capacity after 100 cycles at 20 mA g−1. The charge compensation during charge/discharge is mainly due to the redox couple of Ni2+/Ni3+ in the host with a small amount of contribution from oxygen. The stable structure of the material without phase transformation and with small volume change during charge‐discharge allows it to give excellent cycle performance especially when the upper cutoff voltage is not higher than 4.2 V. [ABSTRACT FROM AUTHOR]

The increasing number of accidents relating to battery fire and explosion is raising people's attention towards safety of batteries. Abnormal battery operation can generate much heat and cause thermal runaway due to the exothermic reactions of the electrodes and electrolyte. Recently, dual‐ion battery (DIB) has gained many interests because of its low cost and high working voltage compared with traditional lithium‐ion battery (LIB). However, investigation on thermal stability of DIB is rare. In this paper, differential scanning calorimetry (DSC) was used to study the thermal stability of DIB using graphite as cathode with different states of charge (SOC) and with different amount of fluoroethylene carbonate as co‐solvent in the electrolyte. Then, the thermal stability of graphite cathode for DIB was compared with those of LiCoO2 and LiNi0.5Mn1.5O4 at their fully charged states. Specifically, charged DIB using graphite as cathode in 3 m LiPF6 EMC showed superior thermal stability with no exothermic peaks in DSC tests, in contrast to traditional lithium‐containing cathodes for LIB, which gave out significant amount of heat at evaluated temperature. In addition, the thermal stability of graphite depended on the type of intercalation species in it. While PF6− intercalated graphite [Cn(PF6)] showed an endothermic peak at about 320 °C, Li+ intercalated graphite [Cn(Li)] showed an exothermic peak at about 300 °C. Moreover, the type of electrolyte also affected heat generation from the charged electrodes and should be properly designed to improve thermal stability in the future. [ABSTRACT FROM AUTHOR]

Cu−Li batteries leveraging the two‐electron redox property of Cu can offer high energy density and low cost. However, Cu−Li batteries are plagued by limited solubility and a shuttle effect of Cu ions in traditional electrolytes, which leads to low energy density and poor cycling stability. In this work, we rationally design a solid‐state sandwich electrolyte for solid‐state Cu−Li batteries, in which a deep‐eutectic‐solvent gel with high Cu‐ion solubility is devised as a Cu‐ion reservoir while a ceramic Li1.4Al0.4Ti1.6(PO4)3 interlayer is used to block Cu‐ion crossover. Because of the high ionic conductivity (0.55 mS cm−1 at 25 °C), wide electrochemical window (>4.5 V vs. Li+/Li), and high Cu ion solubility of solid‐state sandwich electrolyte, a solid‐state Cu−Li battery demonstrates a high energy density of 1 485 Wh kgCu−1and long‐term cyclability with 97 % capacity retention over 120 cycles. The present study lays the groundwork for future research into low‐cost solid‐state Cu−Li batteries. [ABSTRACT FROM AUTHOR]

The dual‐ion battery (DIB) is a promising energy storage system that demonstrates high‐power characteristics and fast‐charging capability. However, conventional electrolytes are not compatible with the high‐voltage graphite cathode and the reactive Li metal anode, thus leading to the poor cycle stability and low Coulombic efficiency of the DIB. Here, an all‐fluorinated electrolyte is reported that can enable a highly stable operation of the graphite||Li DIB up to 5.2 V by forming robust and less‐resistive passivation films on both electrodes to reduce side reactions. The electrolyte allows reversible PF6– anion insertion/extraction and Li+ cation plating/stripping in the graphite||Li battery, achieving stable cycling with 94.5% capacity retention over 5000 cycles at 500 mA g–1, high capacity utilization of 91.8% of the available charge capacity at 50 C (5000 mA g–1), and also minimal self‐discharge. At a low temperature of 0 °C, this all‐fluorinated electrolyte exhibits 97.8% of the room temperature reversible capacity, along with ≈100% capacity retention after more than 3000 cycles, at 5 C. This work sheds a new light on the development of fluorinated electrolytes for high voltage and long‐lasting DIBs. [ABSTRACT FROM AUTHOR]

Novel derivatives of 4,4‐difluoro‐1,3,5,7,8‐pentamethyl‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) functionalized at the meso‐position with polyamines and polyoxyethylenes were synthesized through single‐step condensation of fluorogenic 8‐CH2Cl‐substituted BODIPY and corresponding amines. The systematic spectroscopic characterization (UV‐Vis, fluorescence) of stable in storage dyes bearing polyoxyethylene substituents was carried out. One compound showed promise for UV‐Vis and "off‐on" fluorescence Cu2+ detection in acetonitrile solutions. The ligand detects Cu2+ ions selectively in the presence of eighteen different alkaline earth metal cations. [ABSTRACT FROM AUTHOR]

Sodium–sulfur batteries have attracted attention due to their high energy capacities and low costs, but the dissolution of sodium polysulfides still severely affects their cycle life, limiting their real‐world applications. Herein, a stable sulfur host is reported, based on a N,O‐codoped carbon composite derived from a bimetallic Cu–Zn metal‐organic framework, which ensures high sulfur loading (67 wt%). Most importantly, this composite also includes single‐atom copper catalysts, with a high Cu loading of 8.03 wt%. Solid‐state nuclear magnetic resonance, synchrotron X‐ray absorption spectroscopy, and single‐crystal X‐ray diffraction analysis show that single atoms of Cu are coordinated with two N and two O atoms within the produced composite material. Those copper sites can weaken SS bonds in the S8 ring structure, and thus are able to catalyze the formation of short‐chain sulfur molecules in even larger‐size pores. In addition, Cu atoms facilitate the conversion between the short‐chain sulfur and Na2S. As a result, when the produced sulfur‐loaded carbon framework containing the atomic Cu catalyst is used as a cathode for sodium–sulfur batteries, it exhibits superior capacity of 776 mAh g–1 with a high sulfur utilization (1158 mAh gs–1 normalized with sulfur content) after 100 cycles at 0.1 A g–1, and an excellent rate performance of 483 mAh g–1 (720 mAh gs–1) at 5 A g–1. [ABSTRACT FROM AUTHOR]

Background and objectives: COVID‐19 convalescent plasma is an experimental treatment against SARS‐CoV‐2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS‐CoV2 in convalescent plasma. Materials and methods: A total of 140 plasma doses collected by plasmapheresis from COVID‐19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS‐CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S‐ and N‐proteins of SARS‐CoV‐2 were measured before and after pathogen reduction. Results: The methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one‐step (two‐step, respectively) decrease. Paired two‐sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment. Conclusion: Pathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID‐19 convalescent plasma compared to riboflavin. [ABSTRACT FROM AUTHOR]

Low‐cost and environment‐friendly dual‐ion batteries (DIBs) with fast‐charging characteristics facilitate the development of high‐power energy storage devices. However, the incompatibility between the cathode and electrolyte at high voltage results in low Coulombic efficiency (CE) and short lifespan. Here, the addition of ≈0.5 wt% lithium difluoro(oxalate) borate salt into the electrolyte forms a robust and durable cathode–electrolyte interface (CEI) in situ on the graphite surface, which enables remarkable cycling of the graphite||Li battery with 87.5% capacity retention after 4000 cycles at 5 C and ultrafast rate capability with 88.8% capacity retention under 40 C (4 A g−1), delivering high‐power of 0.4–18.8 kW kg−1 at energy densities of 422.7–318.8 Wh kg−1. Taking advantage of this robust CEI, a graphite||graphite full battery demonstrates high reversible capacities of 97.6, 92.8, 88.7, and 85.4 mAh (g cathode)−1 at current rates of 10, 20, 30, and 40 C, respectively. The full battery also shows a long cycling life of over 6500 cycles with 92.4% capacity retention and an average CE of ≈99.4% at 1 A g−1, which is superior to other dual‐graphite (carbon) batteries in the literature. This work offers an effective interface‐stabilizing strategy on protecting graphite cathodes and a promising approach for developing DIBs with high‐power capability. [ABSTRACT FROM AUTHOR]

Layered transition metal oxides are promising cathode materials for sodium‐ion batteries applicable for low‐cost energy storage systems. However, their cycle stability needs to be substantially improved to meet the requirements of practical applications. Specifically, the issues related to electrolyte stability and the formation of an unstable cathode–electrolyte interface (CEI) remain unsolved. Herein, it is shown that an electrolyte with high fluorine content may induce a robust fluorinated CEI on Na2/3Ni1/3Mn2/3O2 cathode, a representative transitional metal oxide, which can efficiently passivate its surface and suppress continuous electrolyte decomposition during cycling. As a result, the cells deliver a remarkably improved rate capability and cycle stability. Density functional simulations further validate the superior stability of fluorinated electrolyte on cathodes with low highest occupied molecule orbital energy and high dissociation energy barriers. This finding demonstrates the favorable role of fluorinated electrolytes for improving the long‐term cycle stability of Na2/3Ni1/3Mn2/3O2 cathode toward grid‐scale applications. [ABSTRACT FROM AUTHOR]

Herein, phase formation and sintering of hafnium carbonitride ceramics from a 4HfC–3HfN powder mixture using reactive spark plasma sintering are studied. X‐ray diffraction (XRD) data show that the mutual heterodiffusion of carbon C and nitrogen N increases with sintering temperature within the studied temperature range 1500–2100 °C. 4HfC–3HfN powder sintering at 1900 °C for 5 min under 60 MPa pressure yields HfCxN1−x solid solution ceramics. The ceramic sample prepared under optimal conditions (2100 °C, 5 min, 60 MPa) is characterized by an average grain size of 10 μm, microhardness of 19.6–22.5 GPa, and relative density above ≈97%. [ABSTRACT FROM AUTHOR]

Practical applications of room temperature sodium–sulfur batteries are still inhibited by the poor conductivity and slow reaction kinetics of sulfur, and dissolution of intermediate polysulfides in the commonly used electrolytes. To address these issues, starting from a novel 3D Zn‐based metal–organic framework with 2,5‐thiophenedicarboxylic acid and 1,4‐bis(pyrid‐4‐yl) benzene as ligands, a S, N‐doped porous carbon host with 3D tubular holes for sulfur storage is fabricated. In contrast to the commonly used melt‐diffusion method to confine sulfur physically, a vapor‐infiltration method is utilized to achieve sulfur/carbon composite with covalent bonds, which can join electrochemical reaction without low voltage activation. A polydopamine derived N‐doped carbon layer is further coated on the composite to confine the high‐temperature‐induced gas‐phase sulfur inside the host. S and N dopants increase the polarity of the carbon host to restrict diffusion of sulfur, and its 3D porous structure provides a large storage area for sulfur. As a result, the obtained composite shows outstanding electrochemical performance with 467 mAh g−1 (1262 mAh g−1(sulfur)) at 0.1 A g−1, 270 mAh g−1 (730 mAh g−1(sulfur)) after 1000 cycles at 1 A g−1 and 201 mAh g−1 (543 mAh g−1(sulfur)) at 5.0 A g−1. [ABSTRACT FROM AUTHOR]

Metals are attractive materials for energy storage as they can undergo oxidation to accommodate charge transfer. However, traditional metal‐metal batteries such as Cu−Zn have low voltage because of the use of an aqueous electrolyte. Here, we propose a metal‐metal battery system with higher voltage in aprotic electrolyte with Ag/AgCl and Li/Li+ reactions on the cathode and anode, respectively. The Ag−Li cell gives a voltage of about 2.8 V and a capacity of close to 200 mAh g−1. X‐ray diffraction confirms the formation of AgCl during charging. The reduction of AgCl is faster than oxidation of Ag, so the battery has better discharge rate performance than charge. We also find that the solubility of the charge product (AgCl) in the electrolyte influences the cycle stability of the battery. [ABSTRACT FROM AUTHOR]

Herein, we report the systematic evaluation of the BODIPY series functionalized with pseudo‐crown ethers against metal cations and assessment of their potential as novel off‐on fluorescent probes selective for aluminum(III) cations. [ABSTRACT FROM AUTHOR]

Induction of a robust and long-lived mucosal immune response during vaccination is critical to achieve protection against numerous pathogens. However, traditional injected vaccines are generally poor inducers of mucosal immunity. One of the effective strategies to improve vaccine efficacy is incorporation of adjuvant molecules that enhance and polarize adaptive immune reactions. Effects of Syk-coupled lectin receptor agonists as adjuvants to induce mucosal immune reactions during parenteral immunization are not fully studied. We now report that the agonists trehalose-6,6-dibehenate (TDB), curdlan, and furfurman, which stimulate Dectin-1, Dectin-2, and Mincle, respectively, activate transcription factors (NF-κB, NFAT, and AP-1) to various extents in murine RAW 264.7 macrophages, even though similar pathways are activated. The agonists also elicit differential expression of maturation markers in bone marrow-derived dendritic cells, as well as differential cytokine secretion from these cells and from splenic mononuclear cells. In vivo assays also show that agonists of Dectin-1 and Dectin-2, but not Mincle, induce heavy IgA secretion in intestinal mucosa even when delivered parenterally. Strikingly, this effect appears to be formulation-independent. Collectively, the data suggest that adjuvants based on Dectin-1 and Dectin-2 agonists may significantly improve the efficacy of parenteral vaccines by inducing robust local immune reactions in intestinal mucosa. [ABSTRACT FROM AUTHOR]

Abstract: A vacuum calcination approach is developed to fabricate selenium/carbon composites, which does not require intensive mixing and durable heating such as in commonly used melt‐infusion methods of loading selenium into carbon hosts. Starting from carbon‐coated selenium wires prepared via a wet‐chemical reaction, selenium/carbon tubes are fabricated by a straightforward calcination process. The calcination is conducted in a confined space to reduce the insulating carbon shell under vacuum, and selenium melts but remains a constituting part of the composite. Paired with sodium metal anode, the resultant selenium/carbon tubes deliver a high reversible capacity of 601 and 509 mA h g−1 at 0.2 and 2 C normalized by the mass of selenium, which corresponds to energy and power densities of 860 and 667 Wh kg−1 at 193 and 1770 W kg−1, respectively. Such capacity and rate performance surpasses most typical cathode materials for lithium or sodium (ion) batteries, according to the comparative literature analysis. Moreover, the robust tubular‐like hollow structure of the selenium/carbon composites ensures for impressive capacity retention of more than 90% after 1000 cycles at 20 C. [ABSTRACT FROM AUTHOR]

Na0.7MnO2 is a potential high-capacity cathode material for sodium-ion batteries. Typical Na0.7MnO2 material synthesized with quenching after annealing shows a P2 structure with orthorhombic distortion. However, the material is not stable when stored in ambient atmosphere and shows poor cycle performance during charge/discharge. In this study, we synthesized phase-pure P2-Na0.7(1− x)[Li xMn1− x]Oδ without orthorhombic distortion by adding Li into the precursor. We show that the material can be synthesized even with natural cooling, and is stable when exposed to air. Electrochemical tests and ex situ X-ray diffraction studies reveal that the phase-pure material exhibits fewer phase transitions and less structural degradation upon Na+ de-intercalation/intercalation, resulting in enhanced cycle performance. For example, Na0.64[Li0.09Mn0.91]O2.07 delivers an initial discharge capacity of 170.9 mAh g−1 with capacity retention of 61.1 % (104.4 mAh g−1) after 100 cycles. This is significantly better than the cycle performance of the distorted P2-Na0.7MnOδ tested under the same conditions. [ABSTRACT FROM AUTHOR]

Chlamydia trachomatis imposes serious health problems and causes infertility. Because of asymptomatic onset, it often escapes antibiotic treatment. Therefore, vaccines offer a better option for the prevention of unwanted inflammatory sequelae. The existence of serologically distinct serovars of C. trachomatis suggests that a vaccine will need to provide protection against multiple serovars. Chlamydia spp. use a highly conserved type III secretion system (T3SS) composed of structural and effector proteins which is an essential virulence factor. In this study, we expressed the T3SS needle protein of Chlamydia muridarum, TC_0037, an ortholog of C. trachomatis CdsF, in a replication-defective adenoviral vector (AdTC_0037) and evaluated its protective efficacy in an intravaginal Chlamydia muridarum model. For better immune responses, we employed a heterologous prime-boost immunization protocol in which mice were intranasally primed with AdTC_0037 and subcutaneously boosted with recombinant TC_0037 and Toll-like receptor 4 agonist monophosphoryl lipid A mixed in a squalene nanoscale emulsion. We found that immunization with TC_0037 antigen induced specific humoral and T cell responses, decreased Chlamydia loads in the genital tract, and abrogated pathology of upper genital organs. Together, our results suggest that TC_0037, a highly conserved chlamydial T3SS protein, is a good candidate for inclusion in a Chlamydia vaccine. [ABSTRACT FROM AUTHOR]

Silicon is a potential high-capacity anode material for lithium-ion batteries. However, large volume changes in the material remains a bottleneck to its commercialization. Many works have been devoted to nanostructured composites with voids to accommodate the volume expansion. Yet, the full capability of silicon cannot be utilized, because these nanostructured electrodes have low volumetric capacities. Herein, we redesign dense silicon electrodes with three times the volumetric capacity of graphite. In situ electrochemical dilatometry reveals that the electrode thickness change is nonlinear as a function of state of charge and highly affected by the electrode composition. One key problem is the large vertical displacement of the silicon particles during lithiation, which leads to irreversible particle detachment and electrode porosity increase. Better reversibility in electrode thickness changes can be achieved by using polyimide, with a higher modulus and larger ultimate elongation, as the binder, leading to better cycle stability. [ABSTRACT FROM AUTHOR]

In laboratory experiments, Li-O2 systems show 'sudden death' at capacities far below the theoretical value. Identifying how discharge products limit the total capacity is crucial in Li-O2 system. We investigated the effect of Li2O2 seed layer deposited on carbon cathode under potentiostatic conditions at increasing overpotentials to the subsequent slow discharge at galvanostatic condition. The discharge capacity attainable in the second step is found to vary by more than a factor of 3 depending on the history, i.e., the seed layer. These results provide evidence that the battery history is decisive for the total discharge capacities. [ABSTRACT FROM AUTHOR]

Using a sample of export intermediaries connecting domestic producers and foreign buyers, the study tests competing hypotheses on firm performance derived from the Austrian and transaction cost perspectives. Specifically, the Austrian perspective suggests that the more distant the export market and the more complex the product that the intermediary specializes in, the better its performance. Transaction cost theory, on the other hand, offers conflicting predictions. Our results indicate that these two theories are complementary to each other, and a contingency framework is proposed and discussed. [ABSTRACT FROM AUTHOR]

By understanding how structural transitions affect the electrochemical performance of a battery, better electrode materials for reversible Na+ insertion/extraction can be developed. Here, the structural evolution of the recently synthesized P2 phases of Na0.7Li0.1Mn0.9O2 and Na2/3Cu1/3Mn2/3O2 using high‐resolution in situ synchrotron X‐ray diffraction experiments is reported and the evolution relative to the parent P2 Na0.7MnO2 is directly compared. All electrodes feature solid solution and two‐phase reactions during charge/discharge/charge processes. Using a simplified single‐phase evolution for comparative purposes, the P2 Na0.7Li0.1Mn0.9O2 and P2 Na2/3Cu1/3Mn2/3O2 show volume changes of 1.909(1) and 1.13(3) Å3 of the major phase, respectively, during charge/discharge while the parent P2 Na0.7MnO2 shows an overall volume change of 0.67(0) Å3 for P2 and 61.9(1) Å3 for orthorhombic phase. The maximum volume for P2 Na0.7Li0.1Mn0.9O2 of 81.094(6) Å3 is observed at 2.35 V during discharge while for P2 Na2/3Cu1/3Mn2/3O2 of 81.753(6) Å3 is observed at the discharged state (1.5 V). Compared to the P2 Na0.7MnO2 the number of phase transitions experienced by the P2 Na0.7Li0.1Mn0.9O2 and P2 Na2/3Cu1/3Mn2/3O2 are significantly smaller. Li/Cu‐doped samples generally show better cycle performance, and these results illustrate the structural response such substitutions have on the Na+ insertion/extraction of P2 Na0.7MnO2 during cycling. In situ synchrotron X‐ray diffraction is employed to track and compare the crystal structure evolution of three‐layered "P2‐type" cathode materials pertinent for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

In terms of applications for sodium‐ion batteries, titania shows several compelling features, such as environmental availability, favorable sodiation potential, and long cycle lifespan, but it also possesses several drawbacks such as the low utilization and low initial coulombic efficiency (ICE). A double‐fold carbon incorporation strategy of improving titania anode materials, namely coating titania nanoparticles with polypyrrole (PPY) and integrating them into a carbon nanotube (CNT) network, is introduced. This treatment not only ensures direct contact of individual titania nanoparticles with the conductive components in the composite but also builds a 3D interconnecting CNT framework to facilitate both mass and charge transfer. The TiO2/PPY/CNT composite delivers reversible capacity of 252 and 201 mAh g−1 at 0.1 and 1 C, respectively; achieves an ICE of 70%, which is the highest value so far, in an ether‐based electrolyte; and retains nearly 80% of its capacity in a 3000‐cycle test. Co‐compositing titania with PPY and CNT guarantees both efficient electrical connection of active materials and resilience against cycling, and this strategy is feasible for various electrode materials which usually need carbon incorporation to improve capacity and stabilize cycling. Anatase TiO2 nanoparticles are coated with a conductive polymer (polypyrrole) and then integrated into an interwoven carbon nanotube network. The resultant composite, as an anode for sodium‐ion batteries, delivers significantly enhanced rate capability and shows high cycle stability in an ether‐based electrolytes, and its initial coulombic efficiency outperforms TiO2‐based anodes which have been reported in the literature, so far. [ABSTRACT FROM AUTHOR]