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Recently, Ru single atoms supported on carbon nanomaterials have demonstrated ultrahigh activity for acid hydrogen evolution reaction (HER), however their neutral HER activity remains low due to the sluggish kinetics for both the water dissociation step to generate H* intermediates and subsequent H* recombination in neutral electrolytes. Here, we synthesize ordered low-coordinated Ru atom arrays confined in Mn oxides (i.e., Li4Mn5O12) for concurrently boosting the water dissociation and H* recombination, thus achieving a 6-fold HER activity enhancement than commercial Pt/C in neutral media. Control experiments indicate that low-coordinated Ru atoms with strong affinity to oxygen atoms of water molecules facilitate the water dissociation to rapidly generate H*. More importantly, both electrochemical and theoretic results uncover that the array-like structure allows the activation of two water molecules on two adjacent Ru atoms for enabling direct H*-H* recombination via the Tafel step, while isolated Ru atoms can only activate water one by one for recombining H* via the sluggish Heyrovsky step. Clearly, this work paves new avenues to boosting the electrocatalytic activity by constructing ordered metal atoms assembles with controllable coordination environments., (© 2024 Wiley‐VCH GmbH.)

Membranes with precise Li + /Na + and Li + /K + separations are imperative for lithium extraction from brine to address the lithium supply shortage. However, achieving this goal remains a daunting challenge due to the similar valence, chemical properties, and subtle atomic-scale distinctions among these monovalent cations. Herein, inspired by the strict size-sieving effect of biological ion channels, a membrane is presented based on nonporous crystalline materials featuring structurally rigid, dimensionally confined, and long-range ordered ion channels that exclusively permeate naked Li + but block Na + and K + . This naked-Li + -sieving behavior not only enables unprecedented Li + /Na + and Li + /K + selectivities up to 2707.4 and 5109.8, respectively, even surpassing the state-of-the-art membranes by at least two orders of magnitude, but also demonstrates impressive Li + /Mg 2+ and Li + /Ca 2+ separation capabilities. Moreover, this bioinspired membrane has to be utilized for creating a one-step lithium extraction strategy from natural brines rich in Na + , K + , and Mg 2+ without utilizing chemicals or creating solid waste, and it simultaneously produces hydrogen. This research has proposed a new type of ion-sieving membrane and also provides an envisioning of the design paradigm and development of advanced membranes, ion separation, and lithium extraction., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Helicobacter pylori (HP), a common microanaerobic bacteria that lives in the human mouth and stomach, is reported to infect ≈50% of the global population. The current diagnostic methods for HP are either invasive, time-consuming, or harmful. Therefore, a noninvasive and label-free HP diagnostic method needs to be developed urgently. Herein, reduced graphene oxide (rGO) is composited with different metal-based materials to construct a graphene-based electronic nose (e-nose), which exhibits excellent sensitivity and cross-reactive response to several gases in exhaled breath (EB). Principal component analysis (PCA) shows that four typical types of gases in EB can be well discriminated. Additionally, the potential of the e-nose in label-free detection of HP infection is demonstrated through the measurement and analysis of EB samples. Furthermore, a prototype of an e-nose device is designed and constructed for automatic EB detection and HP diagnosis. The accuracy of the prototype machine integrated with the graphene-based e-nose can reach 92% and 91% in the training and validation sets, respectively. These results demonstrate that the highly sensitive graphene-based e-nose has great potential for the label-free diagnosis of HP and may become a novel tool for non-invasive disease screening and diagnosis., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Direct seawater splitting (DSS) offers an aspirational route toward green hydrogen (H 2 ) production but remains challenging when operating in a practically continuous manner, mainly due to the difficulty in establishing the water supply-consumption balance under the interference from impurity ions. A DSS system is reported for continuous ampere-level H 2 production by coupling a dual-cation exchange membrane (CEM) three-compartment architecture with a circulatory electrolyte design. Monovalent-selective CEMs decouple the transmembrane water migration from interferences of Mg 2+ , Ca 2+ , and Cl - ions while maintaining ionic neutrality during electrolysis; the self-loop concentrated alkaline electrolyte ensures the constant gradient of water chemical potential, allowing a specific water supply-consumption balance relationship in a seawater-electrolyte-H 2 sequence to be built among an expanded current range. Even paired with commercialized Ni foams, this electrolyzer (model size: 2 × 2 cm 2 ) continuously produces H 2 from flowing seawater with a rate of 7.5 mL min -1 at an industrially relevant current of 1.0 A over 100 h. More importantly, the energy consumption can be further reduced by coupling more efficient NiMo/NiFe foams (≈6.2 kWh Nm -3 H 2 at 1.0 A), demonstrating the potential to further optimize the continuous DSS electrolyzer for practical applications., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

The introduction of battery-type cathode has been commonly considered a preferred approach to boost the energy density of aqueous hybrid energy storage devices (AHESDs) in alkalic systems, but AHESDs with both high energy density and power density are rare due to the great challenge in designing battery-type anode materials with high rate and durability comparable to capacitive-type carbon anodes. In this paper, a well-hydrated iron selenate (FeSeO) sheath is constructed around FeOOH nanorods by a facile electrochemical activation, demonstrating the unique multifunction in fasting charge diffusion, promoting the dissociation of H 2 O, and inhibiting the irreversible phase transition of FeOOH to inert γ-Fe 2 O 3 , which endow the hydrated sheath coated Fe-based anodes with an impressive rate capability and superior durability. Thanks to the comprehensive performance of this Fe-based anode, the assembled AHESD delivered a high energy density of 117 Wh kg -1 with the extraordinary durability of almost 100% capacity retention after 40 000 cycles. Even at an ultrahigh power density of 27 000 W kg -1 , an impressive energy density of 65 Wh kg -1 can be achieved, which rivals previously reported energy-storage devices., (© 2024 Wiley‐VCH GmbH.)

Stem cell tissue engineering is a potential treatment for osteoarthritis. However, the number of stem cells that can be delivered, loss of stem cells during injection, and migration ability of stem cells limit applications of traditional stem cell tissue engineering. Herein, kartogenin (KGN)-loaded poly(lactic-co-glycolic acid) (PLGA) porous microspheres is first engineered via emulsification, and then anchored with chitosan through the amidation reaction to develop a new porous microsphere (PLGA-CS@KGN) as a stem cell expansion vector. Following 3D co-culture of the PLGA-CS@KGN carrier with mesenchymal stem cells (MSCs), the delivery system is injected into the capsule cavity in situ. In vivo and in vitro experiments show that PLGA-CS microspheres have a high cell-carrying capacity up to 1 × 10 4 mm -3 and provide effective protection of MSCs to promote their controlled release in the osteoarthritis microenvironment. Simultaneously, KGN loaded inside the microspheres effectively cooperated with PLGA-CS to induce MSCs to differentiate into chondrocytes. Overall, these findings indicate that PLGA-CS@KGN microspheres held high cell-loading ability, adapt to the migration and expansion of cells, and promote MSCs to express markers associated with cartilage repair. Thus, PLGA-CS@KGN can be used as a potential stem cell carrier for enhancing stem cell therapy in osteoarthritis treatment., (© 2023 Wiley-VCH GmbH.)

Aqueous zinc-ion batteries (AZIBs) assembled with gel polymer electrolyte (GPE) have gained great popularity due to their low cost and safety. Nevertheless, the extensive utilization of GPE based AZIBs is hindered by various challenges, such as inadequate conductivity, limited mechanical strength, and unstable electrochemical properties. Herein, through the multiple cross-linking reaction of sodium alginate (SA), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP) and graphene oxide (GO), a hydrated GPE with high conductivity and excellent mechanical property was prepared. GO formed strong hydrogen-bonding interaction with polymers to build a three-dimensional network structure for ion migration and improved the mechanical property of GPE. The prepared GPE showed high ionic conductivity of 2.89×10 -3  S cm -1 and excellent tensile strength of 900 kPa. In addition, the assembled Zn-Li hybrid battery provided a discharge specific capacity retention rate of 67.6 % and a Coulombic efficiency (CE) of approximate 100 % after 1000 cycles at 1 C., (© 2023 Wiley-VCH GmbH.)

Hydrogel electrolytes hold great promise in developing flexible and safe batteries, but the presence of free solvent water makes battery chemistries constrained by H 2 evolution and electrode dissolution. Although maximizing salt concentration is recognized as an effective strategy to reduce water activity, the protic polymer matrices in classical hydrogels are occupied with hydrogen-bonding and barely involved in the salt dissolution, which sets limitations on realizing stable salt-concentrated environments before polymer-salt phase separation occurs. Inspired by the role of protein methylation in regulating intracellular phase separation, here we transform the "inert" protic polymer skeletons into aprotic ones through methylation modification to weaken the hydrogen-bonding, which releases free hydrogen bond acceptors as Lewis base sites to participate in cation solvation and thus assist salt dissolution. An unconventionally salt-concentrated hydrogel electrolyte reaching a salt fraction up to 44 mol % while retaining a high Na + /H 2 O molar ratio of 1.0 is achieved without phase separation. Almost all water molecules are confined in the solvation shell of Na + with depressed activity and mobility, which addresses water-induced parasitic reactions that limit the practical rechargeability of aqueous sodium-ion batteries. The assembled Na 3 V 2 (PO 4 ) 3 //NaTi 2 (PO 4 ) 3 cell maintains 82.8 % capacity after 580 cycles, which is the longest cycle life reported to date., (© 2023 Wiley-VCH GmbH.)

Magnesium (Mg) metal secondary batteries have attracted much attention for their high safety and high energy density characteristics. However, the significant issues of the cathode/electrolyte interphase (CEI) in Mg batteries are still being ignored. In this work, a significant CEI layer on the typical Mo 6 S 8 cathode surface has been unprecedentedly constructed through the oxidation of the chloride-free magnesium tetrakis(hexafluoroisopropyloxy)borate (Mg[B(hfip) 4 ] 2 ) salt under a proper charge cut-off voltage condition. The CEI has been identified to contain B x O y effective species originating from the oxidation of [B(hfip) 4 ] - anion. It is confirmed that the B x O y species is beneficial to the desolvation of solvated Mg 2+ , speeding up the interfacial Mg 2+ transfer kinetics, thereby improving the Mg 2+ -storage capability of Mo 6 S 8 host. The firstly reported CEI in Mg batteries will give deeper insights into the interface issues in multivalent electrochemical systems., (© 2023 Wiley-VCH GmbH.)

Dual-ion batteries (DIBs) based on anion (de)intercalation into low-cost graphitic carbon cathodes hold great promise in grid-scale energy storage. Different from the electrolyte in rocking-chair batteries, which only serves as a charge transporter, both cations and anions in the electrolyte for DIBs participate in battery reactions. Hence, the impact of the electrolyte formulation on cycle life, energy density, as well as cost has become a subject of vital importance. This review discussed the challenges and recent progress of electrolytes for DIBs, with a particular focus on the exploration of electrolytes with high oxidation stability, high salt concentration, high ionic conductivity, and low cost. Moreover, the influence of varied ion concentrations at different state-of-charge levels on the electrolyte properties such as ionic conductivity and electrochemical stability is analyzed. Finally, perspectives on the current limitations and future research directions of electrolytes for DIBs are provided., (© 2022 Wiley-VCH GmbH.)

Invited for this month's cover is the group of Weitao Zheng at the Jilin University. The image shows the working mechanism of dual-ion batteries (DIBs). The Review itself is available at 10.1002/cssc.202201375., (© 2023 Wiley-VCH GmbH.)

Uniform magnesium (Mg) plating/stripping under high areal capacity utilization is critical for the practical application of Mg-metal anodes in rechargeable Mg batteries. However, the failure of the Mg-metal anode when cycling under a practical areal capacity (>4 mA h cm -2 ), is of rising concern. The mechanism behind these failures remains controversial. In this work, it is illustrated that the initial plating Mg can be undoubtedly uniform in a wide range of current densities (≤5 mA cm -2 ) and under a practical areal capacity (6 mA h cm -2 ). However, an unusual self-accelerating pit growth is observed in the Mg stripping side under moderate current densities (0.1-1 mA cm -2 ), which severely deteriorates the anode integrity and subsequent Mg plating uniformity, causing failure of the Mg-metal anode or short circuit of the battery. The stripping morphology depends on the applied current density, as non-uniformity versus the current density displays a volcano plot during the stripping process. Through in situ spectroscopy, it is illustrated that this current-dependent behavior is determined by the evolution of chlorine-containing complex ions near the interface. This research reminds that the plating/stripping process of the Mg-metal anode must be considered comprehensively for practical Mg-metal batteries., (© 2022 Wiley-VCH GmbH.)

Chalcogenides have been viewed as important conversion-type Mg 2+ -storage cathodes to fulfill the high volumetric energy density promise of magnesium (Mg) batteries. However, the low initial Columbic efficiency and the rapid capacity degradation remain challenges for the chalcogenide cathodes, as the clear Mg 2+ -storage mechanism has yet to be clarified. Herein, we illustrate that the charge storage mechanism of the Cu 2-x Se cathode is a reversible displacement reaction along with a polyselenide (PSe) mediated solution process of anion-compensation. The unique anion redox improves charge storage, while the dissolution of PSe also leads to performance degradation. To address this issue, we introduce Mo 6 S 8 into the Cu 2-x Se cathode to immobilize PSe, which significantly improves performance, especially the reversible capacity (from 140 mAh g -1 to 220 mAh g -1 ). This work provides inspiration for the modification of the Mg 2+ -storage cathode, which is a milestone for high-performance Mg batteries., (© 2022 Wiley-VCH GmbH.)

Graphitic carbon that allows reversible anion (de)intercalation is a promising cathode material for cost-efficient and high-voltage dual-ion batteries (DIBs). However, one notorious but overlooked issue is the incomplete interfacial anion desolvation, which not only reduces the oxidative stability of electrolytes, but also results in solvent co-intercalation into graphite layers. Here, an "anion-permselective" polymer electrolyte with abundant cationic quaternary ammonium motif is developed to weaken the PF 6 - -solvent interaction and thus facilitates PF 6 - desolvation. This strategy significantly inhibits solvent co-intercalation as well as enhances the oxidation resistance of electrolyte, ensuring the structural integrity of graphite. As a result, the as-assembled graphite||Li cell achieves a superior cyclability with an average Coulombic efficiency of 99.0% (vs 95.7% for baseline electrolyte) and 87.1% capacity retention after 2000 cycles even at a high cutoff potential of 5.4 V versus Li + /Li. Besides, this polymer also forms a robust cathode electrolyte interface, working together to enable a long-life DIB. This strategy of tuning anion coordination environment provides a promising solution to regulate solvent co-intercalation chemistry for DIBs., (© 2022 Wiley-VCH GmbH.)

Solid-state zinc (Zn) batteries offer a new candidate for emerging applications sensitive to volume, safety and cost. However, current solid polymeric or ceramic electrolyte structures remain poorly conductive for the divalent Zn 2+ , especially at room temperature. Constructing a heterogeneous interface which allows Zn 2+ percolation is a viable option, but this is rarely involved in multivalent systems. Herein, we construct a solid Zn 2+ -ion conductor by inducing crystallization of tailored eutectic liquids formed by organic Zn salts and bipolar ligands. High-entropy eutectic-networks weaken the ion-association and form interfacial Zn 2+ -percolated channels on the nucleator surfaces, resulting in a solid crystal with exceptional selectivity for Zn 2+ transport (t Zn 2 + =0.64) and appreciable Zn 2+ conductivity (σ Zn 2 + =3.78×10 -5  S cm -1 at 30 °C, over 2 orders of magnitude higher than conventional polymers), and finally enabling practical ambient-temperature Zn/V 2 O 5 metal solid cells. This design principle leveraged by the eutectic solidification affords new insights on the multivalent solid electrochemistry suffering from slow ion migration., (© 2021 Wiley-VCH GmbH.)

The ideal bone repair material should firstly recognize and recruit osteoblast precursor cells to initiate the repair process, then promote the differentiation of osteoblasts and accelerate the mineralization of the extracellular matrix (ECM). Here, a bioinspired staged bone regeneration strategy which loads bone morphogenetic protein 2 (BMP 2 )-modified black phosphorus (BP@BMP 2 ) nanosheets to a polylactic acid (PLLA) electrospun fibrous scaffold, with a combination of recruiting osteoblast precursor cells and biomineralization properties for bone regeneration, is constructed successfully by micro-sol electrospinning technique. BP, acting as carriers, can not only provide a negative surface and a strong BMP 2 loading ability but can also promote biomineralization in a 3D manner on the electrospun fibrous scaffold, while the BMP 2 is to target osteoblast precursor cells for recruitment and osteogenesis differentiation, which endows BP@BMP 2 nanosheets with staged bone regeneration ability. Furthermore, the in vitro and in vivo data showed that the BP@BMP 2 loaded electrospun fibrous scaffold have good biocompatibility and a strong osteogenesis ability resulting in rapid new bone tissue regeneration. Altogether, this newly developed bioinspired BMP 2 -modified BP electrospun fiber with staged bone regeneration properties via recruiting osteoblast precursor cells to the bone injured site and accelerating biomineralization can be a promising approach in physiologic bone repair., (© 2020 Wiley-VCH GmbH.)

Conventional carbonate solvents with low HOMO levels are theoretically compatible with the low-cost, high-voltage chemistry of Zn/graphite batteries. However, the nucleophilic attack of the anion on carbonates induces an oxidative breakdown at high potentials. Here, we restore the inherent anodic stability of carbonate electrolytes by designing a micro-heterogeneous anion solvation network. Based on the addition of a strongly electron-donating solvent, trimethyl phosphate (TMP), the oxidation-vulnerable anion-carbonate affinities are decoupled because of the preferential sequestration of anions into solvating TMP domains around the metal cations. The hybridized electrolytes elevate the electrochemical window of carbonate electrolytes by 0.45 V and enable the operation of Zn/graphite dual-ion cells at 2.80 V with a long cycle life (92 % capacity retention after 1000 cycles). By inheriting the non-flammability from TMP and the high ion-transport kinetics from the carbonate systems, this facile strategy provides cells with the additional benefits of fire retardancy and high-power capability., (© 2020 Wiley-VCH GmbH.)

It is demonstrated that a novel eutectic solution including 1,3,5-trioxane (TXE) and succinonitrile (SN) can be converted into solid-state polymer electrolyte (SPE) via in situ polymerization triggered by lithium difluoro(oxalato)borate (LiDFOB). It is worth noting that all the precursors (LiDFOB, TXE, and SN) of this novel SPE are totally solid and nonvolatile at room temperature, where, LiDFOB works as a lithium salt and an initiator simultaneously to avoid the introduction of impurity. It is noted that such SPE presents a considerable ionic conductivity of 1.14 × 10 -4 S cm -1 and a sufficiently wide electrochemical window of 4.5 V, which is significant for supporting the high-energy lithium batteries. In addition, this dedicatedly designed in situ polymerization is powerful to build kinetically favorable polymer-based protective layers on LiCoO 2 cathode and Li metal anode simultaneously, guaranteeing outstanding cycling stability (capacity retention of 88% after 200 cycles) of 4.3 V LiCoO 2 /lithium metal batteries at room temperature. More intriguingly, soft packed LiCoO 2 /SPE/Li metal batteries can still light a blue light emitting diode (LED) under the harsh conditions of being bent, cut, and stroked by a hammer, demonstrating excellent safety characteristics., Competing Interests: The authors declare no conflict of interest., (© 2020 The Authors. Published by Wiley‐VCH GmbH.)

There is a long-standing consciousness that the rhombohedral NASICON-type compounds as promising cathodes for Li + /Na + batteries should have inactive M1(6b) sites with ion (de)intercalation occurring only in the M2 (18e) sites. Of particular significance is that M1 sites active for charge/discharge are commonly considered undesirable because the ion diffusion tends to be disrupted by the irregular occupation of channels, which accelerates the deterioration of battery. However, it is found that the structural stability can be substantially improved by the mixed occupation of Na + /Zn 2+ at both M1 and M2 when using NaV 2 (PO 4 ) 3 (NVP) as a cathode for Zn-ion batteries. The results of atomic-scale scanning transmission electron microscopy, analysis of ab initio molecular dynamics simulations, and an accurate bond-valence-based structural model reveal that the improvement is due to the facile migration of Zn 2+ in NVP, which is enabled by a concerted Na + /Zn 2+ transfer mechanism. In addition, significant improvement of the electronic conductivity and mechanical properties is achieved in Zn 2+ -intercalated ZnNaV 2 (PO 4 ) 3 in comparison with those of Na 3 V 2 (PO 4 ) 3 . This work not only provides in-depth insight into Zn 2+ intercalation and dynamics in NVP unlocked by activating the M1 sites, but also opens a new route toward design of improved NASICON cathodes., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Rechargeable magnesium (Mg) metal batteries are a promising candidate for "post-Li-ion batteries" due to their high capacity, high abundance, and most importantly, highly reversible and dendrite-free Mg metal anode. However, the formation of passivating surface film rather than Mg 2+ -conducting solid electrolyte interphase (SEI) on Mg anode surface has always restricted the development of rechargeable Mg batteries. A stable SEI is constructed on the surface of Mg metal anode by the partial decomposition of a pristine Li electrolyte in the electrochemical process. This Li electrolyte is easily prepared by dissolving lithium tetrakis(hexafluoroisopropyloxy)borate (Li[B(hfip) 4 ]) in dimethoxyethane. It is noteworthy that Mg 2+ can be directly introduced into this Li electrolyte during the initial electrochemical cycles for in situ forming a hybrid Mg 2+ /Li + electrolyte, and then the cycled electrolyte can conduct Mg-ion smoothly. The existence of this as-formed SEI blocks the further parasitic reaction of Mg metal anode with electrolyte and enables this electrolyte enduring long-term electrochemical cycles stably. This approach of constructing superior SEI on Mg anode surface and exploiting novel Mg electrolyte provides a new avenue for practical application of high-performance rechargeable Mg batteries., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A polymer-based magnesium (Mg) electrolyte is vital for boosting the development of high-safety and flexible Mg batteries by virtue of its enormous advantages, such as significantly improved safety, potentially high energy density, ease of fabrication, and structural flexibility. Herein, a novel polytetrahydrofuran-borate-based gel polymer electrolyte coupling with glass fiber is synthesized via an in situ crosslinking reaction of magnesium borohydride [Mg(BH 4 ) 2 ] and hydroxyl-terminated polytetrahydrofuran. This gel polymer electrolyte exhibits reversible Mg plating/stripping performance, high Mg-ion conductivity, and remarkable Mg-ion transfer number. The Mo 6 S 8 /Mg batteries assembled with this gel polymer electrolyte not only work well at wide temperature range (-20 to 60 °C) but also display unprecedented improvements in safety issues without suffering from internal short-circuit failure even after a cutting test. This in situ crosslinking approach toward exploiting the Mg-polymer electrolyte provides a promising strategy for achieving large-scale application of Mg-metal batteries., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Flexible batteries are essential for wearable electronic devices. To meet practical applications, they need to be mechanically robust and stable. However, strong or multiple bending may sever the interfacial contact between electrode and electrolyte, causing capacity fading or even battery failure. Herein we present a new cooling-recovery concept for flexible batteries, which involves a temperature-sensitive sol-gel transition behavior of the thermoreversible polymer hydrogel electrolyte. Once a battery has suffered from strong mechanical stresses, a simple cooling process can refresh the electrode-electrolyte interface. The energy-storage capability can be recovered with a healing efficiency higher than 98 %. It is believed that this study not only offers new valuable insights, but also opens up new perspectives to develop functional wearable devices., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A hierarchical CoNi-sulfide nanosheet array is fabricated via an in situ reduction of CoNi-layered double hydroxide (LDH) nanosheets, then a vulcanization process. The material inherits the morphology of the LDH precursor, consisting of well-distributed CoNi-alloy@CoNi-sulfide nanoparticles with a core-shell structure, and demonstrates promising performance toward hydrazine electrooxidation., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A smart, tumor-trigged, controlled drug release using inorganic "caps" with CO3 (2-) functional groups in electrospun fibers is presented for inhibiting cancer relapse. When the drug-loaded intelligent electrospun fibers encounter pathological acidic environments, the inorganic gates react with the acids and produce CO2 gas, which enables water penetration into the core of the fibers to induce rapid drug release., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Acid-responsive electrospun fibers are fabricated by introducing sodium bicarbonate into PLLA fibers using an emulsion method. This novel electrospun fibrous scaffold exhibits a rapid acid-responsive controlled drug release (early stage) and stable three-dimensional (3D) structure as a tissue engineering scaffold (late stage) for cell growth., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A CoAl-layered double hydroxide (LDH)@poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanoplatelet array (NPA) is grown on a flexible Ni foil substrate as a high-performance pseudocapacitor. The LDH@PEDOT core/shell NPA shows a maximum specific capacitance of 649 F/g (based on the total mass) by cyclic voltammetry (scan rate: 2 mV/s) and 672 F/g by galvanostatic discharge (current density: 1 A/g). Furthermore, the hybrid NPA electrode also exhibits excellent rate capability with a specific energy of 39.4 Wh/kg at a current density of 40 A/g, as well as good long-term cycling stability (92.5% of its original capacitance is retained after 5000 cycles). These performances are superior to those of conventional supercapacitors and LDH NPA without the PEDOT coating. The largely enhanced pseudocapacitor behavior of the LDH@PEDOT NPA electrode is related to the synergistic effect of its individual components: the LDH nanoplatelet core provides abundant energy-storage capacity, while the highly conductive PEDOT shell and porous architecture facilitate the electron/mass transport in the redox reaction., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)