Ultralong Cycle Research Articles

Next‐Generation Ultrathin Lightweight Electrode for pH‐Universal Aqueous Flow Batteries

AbstractAqueous flow batteries (AFBs) are promising long‐duration energy storage system owing to intrinsic safety, inherent scalability, and ultralong cycle life. However, due to the thicker (3–5 mm) and heavier (300–600 g m−2) nature, the current used graphite felt (GF) electrodes still limit the volume/weight power density of AFBs. Herein, a lightweight (≈50 g m−2) and ultrathin (≈0.3 mm) carbon microtube electrode (CME) is proposed derived from a scalable one‐step carbonization of commercial cotton cloth. The unique loose woven structure composed of carbon microtube endows CME with excellent conductivity, abundant active sites, and enhanced electrolyte transport performance, thereby significantly reducing polarization in working AFBs. As a consequence, CME demonstrates excellent cycling performance in pH‐universal AFBs, including acidic vanadium flow battery (maximum power density of 632.2 mW cm−2), neutral Zn‐I2 flow battery (750 cycles with average Coulombic efficiency of 99.6%), and alkaline Zn‐Fe flow battery (energy efficiency over 70% at 200 mA cm−2). More importantly, the estimated price of CME is only 5% of GF (≈3 vs ≈60 $ m−2). Therefore, it is reasonably anticipated that the lightweight and ultrathin CME may emerge as the next generation electrode for AFBs.

Surface Charge Regulation of Graphene by Fluorine and Chlorine Co-Doping for Constructing Ultra-Stable and Large Energy Density Micro-Supercapacitors.

Settling the structure stacking of graphene (G) nanosheets to maintain the high dispersity has been an intense issue to facilitate their practical application in the microelectronics-related devices. Herein, the co-doping of the highest electronegative fluorine (F) and large atomic radius chlorine (Cl) into G via a one-step electrochemical exfoliation protocol isengineered to actualize the ultralong cycling stability for flexible micro-supercapacitors (MSCs). Density functional theoretical calculations unveiled that the F into G can form the "ionic" C─F bond to increase the repulsive force between nanosheets, and the introduction of Cl can enlarge the layer spacing of G as well as increase active sites by accumulating the charge on pore defects. The co-doping of F and Cl generates the strong synergy to achieve high reversible capacitance and sturdy structure stability for G. The as-constructed aqueous gel-based MSC exhibited the superb cycling stability for 500,000 cycles with no capacitance loss and structure stacking. Furthermore, the ionic liquid gel-based MSC demonstrated a high energy density of 113.9mWhcm-3 under high voltage of up to 3.5V. The current work enlightens deep insights into the design and scalable preparation of high-performance co-doped G electrode candidate in the field of flexible microelectronics.

Increased interlayer spacing N-doping Ti3C2Tx MXene-based mezzanine heterostructure for enhanced performance lithium/sodium storage

Structure of the electrode materials play a critical role in electrochemical performance for both lithium-ion batteries and sodium ion batteries. Herein, MXene modified by element doping and compositing metal–organic frameworks (MOF)-based Fe2O3@Carbon nanofibers (CNFs) with a mezzanine heterostructure, is constructed to achieve low interfacial impedance, high specific capacity stability in lithium/sodium storage processes. The prepared mezzanine heterostructure Fe2O3@C@N-Ti3C2Tx composite is highly conductive and mesoporous. During the nitrogen-doping thermal treatment process, the interlayer spacing of Ti3C2Tx MXene was increased, providing wider ion transport channels. Additionally, inert carbon atoms were transformed into electrochemically active nitrogen atoms, leading to the construction of more active centers and surface defects. The spatial confinement of N-Ti3C2Tx MXene during the electrochemical process, effectively mitigating volume expansion and maintaining structural stability upon applied as electrode materials. Benefitting from the unique 3D conductive network, the mezzanine heterostructure Fe2O3@C@N-Ti3C2Tx composite nanofibers exhibits excellent Li/Na storage performance. In LIBs, it delivers a capacity of 226 mAh/g at 10 A/g and retains 314 mAh/g after 2800 ultra-long cycles at 5 A/g. For SIBs, it exhibits a capacity of 135 mAh/g at 5 A/g and maintains 209 mAh/g after 3000 cycles at 2 A/g.

Electronic regulation by constructing RGO/MoCQD/CF double interface to enhance performance in solar cells

The intrinsic defects such as the low electrical conductivity and sluggish kinetics for counter electrode seriously hinder its ability to meet the requirements of daily applications for dye-sensitized solar cells (DSSCs). Herein, to propel the development of DSSCs toward ultra-high stability and fast dynamics, the counter electrode (CE) of RGO/MoCQD/CF nanoreactors are created by sandwiching stable MoC quantum dots (QDs) in two distinct carbon matrices {Reduced Graphene Oxide (RGO) and Carbon Flower (CF)}. The multi-structured nanoreactors both effectively enhance stability of catalysis by forming sandwich structure and offers homogeneous dispersion of MoCQD to avoid its agglomeration. Numerous electrons assemble at the RGO contact, which can disrupt the balanced charge state and and modify the electronic structures of Mo sites to expedite reaction kinetics and I3- catalytic activity, according to studies using density functional theory and X-ray photoelectron spectroscopy. Additionally, the framework also contains the advantage of the vast uniformly dispersed active sites, a fast ion–electron transportation channel, and reactive structures that facilitate electrolyte infiltration. By virtue of integration of multiple advantages, DSSC with RGO/MoCQD/CF CE brings excellent performance, i.e., high PCE (9.08 %) and ultra-long cycling performance (96 h), offering great potential for make use of basically viable DSSC.

Quantum-Sized Co Nanoparticles with Rich Vacancies Enabled the Uniform Deposition of Lithium Metal and Fast Polysulfide Conversion.

The notorious polysulfide shuttling and uncontrollable Li-dendrite growth are the main obstacles to the marketization of Li-S batteries. Herein, a dual-functional material consisting of vacancy-rich quantum-sized Co nanodots anchored on a mesoporous carbon layer (v-Co/meso-C) is proposed. This material exposes more active sites to improve its reaction performance and simultaneously realizes excellent lithiophilicity and sulfiphilicity characteristics in Li-S electrochemistry. As Li metal deposition hosts, v-Co/meso-C shows small nucleation overpotential, low polarization, and ultra-long cycling stability in both half and symmetric cells, as confirmed by experimental studies. On the S cathode side, experimental and theoretical calculations demonstrate that v-Co/meso-C enhances the adsorption of polysulfides and boosts their catalytic conversion rate. This, in turn, suppresses the shuttle effect of polysulfides and improves sulfur utilization efficiency. Finally, a shuttle-free and dendrite-free v-Co/meso-C@Li//v-Co/meso-C@S full cell is fabricated, exhibiting excellent rate performance (739 mAhg-1 at 5.0 C) and good cyclability (capacity decay rate is 0.033% and 0.035% per cycle at 2.0 and 5.0 C, respectively). Even a pouch cell with high sulfur loading (5.5mgcm-2) and lean electrolyte/sulfur (4.8µLmg-1) can still work 50 cycles with 80% capacity retention rate. This study shows far-reaching implications in the design of dendrite-free, shuttle-free Li-S batteries.

Interfacial double-coordination effect reconstructing anode/electrolyte interface for long-term and highly reversible Zn metal anodes

The highly reversible electrochemical deposition and dissolution of zinc metal anode is a critical feature for the practical application of aqueous zinc-ion batteries (ZIBs). Nevertheless, this process is seriously hindered by the uncontrollable electrodeposition and interfacial side reactions caused by thermodynamically unstable anode/electrolyte interface (AEI). Guided by the electrode/electrolyte interface chemistry, thiamine hydrochloride (TH) as a novel additive is added into traditional ZnSO4 (ZS) electrolyte to induce sustained reversible Zn deposition/stripping. Spectroscopic characterizations and electrochemical tests reveal that TH can adsorbed on the anode surface owning to the strong double-coordination effect between N, S atoms and Zn atoms via Zn-N and Zn-S chemical bonds. In addition, there are polar hydroxyl groups in the TH molecular structure which can form hydrogen bonds with water molecules. Thus, the adsorbed TH layer can not only guide the diffusion of Zn2+ ions and achieve dendrite-free electrodeposition process, but also prevent intimate contact between water and anode to suppress the occurrence of interface side reactions. Based on these benefits, the TH additive achieves an ultra-long stable cycle lifespan to 2045 h at 1 mA cm−2 and 1 mAh cm−2. Even at a higher current density of 5 mA cm−2, prolonged cycling performance about 773 h is demonstrated. Besides, the assembled Zn//NVO full cells reveal excellent capacity retention and rate performance under practical conditions, highlighting the efficient and reliable coordination effect of TH additive at the AEI.

CuS modified graphite from spent Li-ion batteries towards building high energy Na-ion capacitors via solvent-co-intercalation process

Sodium-ion capacitors (NICs) are one of the most modern hybrid energy storage devices, and they involve two different energy storage mechanisms (faradaic and non-faradaic). The NICs are bridging the gap between the Na-ion batteries and the capacitors with enhanced power and energy densities. This work explores a new combination electrode material, i.e., recovered graphite (RG) decorated with copper sulphide (CuS, CS) as the anode for the NIC application, in which graphite undergoes the solvent-co-intercalation process, and CuS adopts the conversion reaction. We also report the possibility of efficient direct recovery of the anode of dead/spent Li-ion batteries and upcycling as a battery-type component for NIC with commercially available activated carbon (AC) as the capacitor-type cathode. First, the Na-storage property is analyzed in the half-cell configuration, where the Na/RG-CS half-cell displayed excellent cyclic stability with a stable specific capacity of 113 mAh g−1 after 500 cycles with >96% coulombic efficiency in ether solutions. With a pre-sodiated form of RG-CS as anode and mass-balanced AC as a cathode, the NIC is fabricated. The NIC displayed a superior energy density of 64.6 Wh kg−1 with ultra-long cyclability for more than 10,000 cycles with >85% capacity retention. The compatibility of the NIC in different environmental conditions is also studied, and the cell renders better performance in all temperature conditions.

Hierarchical nanostructure engineering endows ammonium vanadate as high capacity and ultra-long cycle cathode for wide-temperature aqueous zinc-ion batteries

Vanadium-based materials are the most promising cathode materials for Zinc-Ion batteries (ZIBs) due to their rich crystal structures and variable valence states. However, the structural collapse during multiple cycles leads to poor cycle life. Therefore, this work develops a 3-dimensional (3D) hierarchical nanostructure NH4V4O10 microspheres composed of nanosheets by a simple hydrothermal method, which are composed of nanosheets, this hierarchical nanostructure can promote the diffusion kinetics of Zn2+ and effectively mitigate the volume change of NH4V4O10 during the charging and discharging processes. As a result, the ZIBs assembled by the NH4V4O10 cathode exhibits high specific capacity of 522.9 mAh g−1 at 0.1 A g−1 and energy density of 348.96 Wh kg−1 at 215.12 W kg−1. At 20 A g−1, the NH4V4O10//Zn aqueous ZIB has 87.2 % capacity retention after 20,000 cycles. In addition, it exhibits excellent specific capacity and cycling performance over a wide-temperature range. At 10 A g−1, the NH4V4O10//Zn aqueous ZIB only loses 5.1 % capacity after 3500 cycles at −20 °C. Even at a high temperature of 50 °C, the capacity of NH4V4O10 battery is able to maintain 95.8 % after 450 cycles. This work informs the development of aqueous ZIBs for long cycle stability in a wide temperature range.

Achieving stable Zn anodes by reducing desolvation barrier and guiding homogeneous nucleation through zincophilic polymer layer

The real-world commercial application of aqueous zinc-ion batteries (AZIBs) is retarded by the poor stability of Zn anode in aqueous solutions, resulting in annoying dendrite growth and intricate side reactions. Herein, the KI-CHOP polymer with rich hydroxyl groups is decorated on the Zn anode surface to rationally construct a solid-state ion-regulating interface. Combing with elaborate experiments and theoretical calculations, the tremendous zincophilic nucleation sites exposed on the KI-CHOP layer could homogenize the Zn2+ flux passing through the interface and decrease the desolvation barrier of hydrated Zn2+, thus speeding up deposition kinetics. Furthermore, the KI-CHOP coating could serve as a hydrogen-bond breaker to construct a lean-water interface thereby suppressing the parasitic side reactions. As expected, as-obtained KI-CHOP@Zn symmetric cells could deliver ultra-long cyclability for over 2200 h at 1.0 mA cm−2 with an area capacity of 1.0 mAh cm−2 as well as excellent reversibility of repeated plating/stripping of Zn2+. Moreover, the KI-CHOP@Zn//MnO2 full cells also exhibit exceptional long-term durability under 1.0 A g−1 for 2000 cycles and rate performance. The KI-CHOP protective layer in this work paves an inspiration for multifunctional polymer coating and takes a step towards the real-world application for AZIBs.

A Bandgap-Tuned Tetragonal Perovskite as Zero-Strain Anode for Potassium-Ion Batteries.

PIBs are emerging as a promising energy storage system due to high abundance of potassium resources and theoretical energy density, however, progress of PIBs is severely hindered by structural instability and poor cycling of anode material during continual insertion and extraction of larger-sized K+. Hence, developing anode material with structural stability and stable cycling remains a great challenge. Herein, bandgap-tuned Mo-doped and carbon-coated lead titanate (CMPTO) with zero-strain K+ storage is presented as ultra-stable PIBs anode. Mo doping introduces narrowed bandgap and optimized crystal lattice for enhanced intrinsic electron and ion transfer. Demonstrated by in situ XRD characterizations, the crystal structure stays stable with unchanged peak positions, fully revealing zero-strain characteristic of CMPTO anode during potassium storage for stable cyclic capability. Ultimately, CMPTO anode achieved ultra-stable cycling performance of 7000 cycles at 500 mA g-1 with high capacity retention of 90% and considerable specific capacity of 130.9 mAh g-1 after 600 cycles at 100 mA g-1; with relatively large density, CMPTO realized eminent volumetric capacity of 1111.09 mAh cm-3 and ultra-long cycling life of 10000 cycles at 7041 mA cm-3. This work introduces a promisingly new route into developing anode materials with ultra-stable performance for PIBs.

Hydrophilic and Insulative Interface Strategy Against Side Reactions for Dendrite‐Free Zinc Metal Anodes

AbstractThe zinc dendrite growth and the parasitic hydrogen evolution reactions (HER) hinder the commercialization of zinc batteries. To address this, a hydroxyl‐rich Boehmite coating (HR‐BC) strategy is developed that combines excellent electrical insulation and high zinc ion conductivity. The hydrophilic hydroxyl groups facilitate hydrogen bond formation with the hydrated zinc ions, accelerating the de‐solvation process and suppressing the HER. Additionally, the electrically insulative nature of Boehmite prevents the reduction of zinc ions within HR‐BC and results in preferential Zn deposition underneath it, leading to a dendrite‐free “sandwich structure” of HR‐BC//Zn deposition//Zn foil. Symmetric cells using HR‐BC‐Zn electrodes obtain an ultralong and stable cycling lifetime of 1700 h at 5 mA cm−2, along with a high cumulative plating capacity of 4250 mAh cm−2. When paired with a V2O5 cathode, the HR‐BC‐Zn anode demonstrates a high capacitance retention of 90% and an average Coulombic efficiency (CE) of 99.8% after 4000 cycles. Furthermore, when combined with a heteroatoms‐doped carbon (HDC) cathode, the HR–BC–Zn//HDC pouch‐type cell exhibits superior lifetime performance with nearly 100% average CE after 15000 cycles at 3.0 A g−1. This work highlights the effectiveness of hydrophilic and insulative coating strategies in fostering the progression of long‐lasting zinc‐based energy storage systems.

High-Performance p-type organic electrode materials with oxygen atoms as active centers enabled by molecular design and in situ electropolymerization

Redox-active organic molecules are considered to be one type of promising electrode materials for next generation lithium-ion batteries (LIBs), among which p-type electrode materials with higher voltage and outstanding reaction kinetics receive much attention. However, it is a great challenge to develop p-type materials with oxygen atom as the active center and the electrochemical performance of the few reported examples needs significant improvement. Herein, 1,3,5-tri(benzofuran-2-yl)benzene (TBFB) was elaborately designed and facilely synthesized through one-step Suzuki coupling reaction from commercially available raw reagents. When used as p-type electrode material for LIBs, it was found that TBFB with poor solubility can be effectively in situ electropolymerized during the charging process, forming more insoluble polymers. Experimental results demonstrate that TBFB electrode achieves a high specific capacity of 179.1 mAh g−1 and an ultralong cycle life of 8000 cycles. This work manifests the electrochemical performance of p-type organic electrode materials with oxygen atom as active center can be effectively enhanced by rational molecular design and in situ electropolymerization method.

Suppressing Surface Oxidation of Pyrite FeS2 by Cobalt Doping in Lithium Sulfur Batteries.

Lithium-sulfur batteries have emerged as a promising energy storage device due to ultra-high theoretical capacity, but the slow kinetics of sulfur and polysulfide shuttle hinder the batteries' further development. Here, the 10% cobalt-doped pyrite iron disulfide electrocatalyst deposited on acetylene black as a separator coating in lithium-sulfur batteries is reported. The adsorption rate to the intermediate Li2S6 is significantly improved while surface oxidation of FeS2 is inhibited: iron oxide and sulfate, thus avoiding FeS2 electrocatalyst deactivation. The electrocatalytic activity has been evaluated in terms of electronic resistivity, lithium-ion diffusion, liquid-liquid, and liquid-solid conversion kinetics. The coin batteries exhibit ultra-long cycle life at 1C with an initial capacity of 854.7 mAh g-1 and maintained at 440.8 mAh g-1 after 920 cycles. Furthermore, the separator is applied to a laminated pouch battery with a sulfur mass of 326 mg (3.7 mg cm-2) and retained the capacity of 590 mAh g-1 at 0.1 C after 50 cycles. This work demonstrates that FeS2 electrocatalytic activity can be improved when Co-doped FeS2 suppresses surface oxidation and provides a reference for low-cost separator coating design in pouch batteries.

Trace alcohol ether electrolytes with dual-site hydrogen bonds and modulated solvation structures for ultralong-life zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are highly regarded for their affordability, stability, safety, and eco-friendliness. Nevertheless, their practical application is hindered by severe side reactions and the formation of zinc (Zn) dendrites on the Zn metal anode surface. In this study, we employ tetrahydrofuran alcohol (THFA), an efficient and cost-effective alcohol ether electrolyte, to mitigate these issues and achieve ultralong-life AZIBs. Theoretical calculations and experimental findings demonstrate that THFA acts as both a hydrogen bonding donor and acceptor, effectively anchoring H2O molecules through dual-site hydrogen bonding. This mechanism restricts the activity of free water molecules. Moreover, the two oxygen (O) atoms in THFA serve as dual solvation sites, enhancing the desolvation kinetics of [Zn(H2O)6]2+ and improving the deposition dynamics of Zn2+ ions. As a result, even trace amounts of THFA significantly suppress adverse reactions and the formation of Zn dendrites, enabling highly reversible Zn metal anodes for ultralong-life AZIBs. Specifically, a Zn-based symmetric cell containing 2 % THFA achieves an ultralong cycle life of 8,800 h at 0.5 mA cm−2/0.5 mAh cm−2, while a Zn//VO2 full cell containing 2 % THFA maintains a remarkable 80.03 % capacity retention rate at 5 A g−1 over 2,000 cycles. This study presents a practical strategy to develop dendrite-free, cost-effective, and highly efficient aqueous energy storage systems by leveraging alcohol ether compounds with dual-site hydrogen bonding capabilities.

Highly reversible Zn anodes enabled by in-situ construction of zincophilic zinc polyacrylate interphase for aqueous Zn-ion batteries

The irreversibility and low utilization of Zn anode stemming from the corrosion and dendrite growth have largely limited the commercialization of aqueous zinc batteries. Here, a carbonyl-rich polymer interphase of zinc polyacrylate (ZPAA) is spontaneously in-situ constructed on Zn anode to address the above-mentioned dilemmas. The ZPAA interlayer enables fast transport kinetics of Zn2+ and tailors the interfacial electric field for realizing the uniform Zn deposition due to superior zincophilicity, high Zn2+ transference number and inherent ion-diffusion channel. Importantly, acting as a buffer interphase with strong adhesion and isolation of electrolytes, this functional layer effectively protects the Zn electrode against the water-induced erosion and passivation. Remarkably, the ZPAA@Zn electrode realizes an enhanced Coulombic efficiency of 99.71 % within 2200 cycles, delivers an ultra-long cycling stability over 7660 h (>319 days, 1 mA cm−2) and 2460 h (5 mA cm−2) with lower voltage hysteresis. Also, the ZPAA@Zn/MnO2 full cell maintains a high capacity of 114 mAh/g after 2000 cycles, much better that of untreated Zn/MnO2 cell (25 mAh/g). This concept of in-situ fabricating ion-sieve-like polymer interphase provides a facile approach to stabilize Zn anode and further paves a way for high-performance aqueous batteries.

Surface to bulk design empowering Ni-rich layered oxide cathode in sulfide-based All-Solid-State batteries

All-solid-state batteries (ASSBs) employing sulfide solid electrolytes (SSE) and high-nickel layered oxide cathodes have attracted considerable attention, attributed to their superior safety and great potential for high energy densities. However, the interface compatibility between SSE and nickel-rich oxide cathode remains a challenge. Here, a dual-functional strategy of Li6.25La3Zr2Al0.25O12 surface coating and bulk Zr doping in LiNi0.8Co0.1Mn0.1O2 was proposed (NCM811@CD-LLZAO), aiming to enhance the interfacial compatibility toward sulfide-based ASSBs. The fabricated ASSBs exhibit an impressive capacity retention rate of 91.1% after 100cycles at 0.1C and can sustain an ultra-long cycling performance over 1000cycles at 1.0C. Remarkably, even at a high rate of 11.0C, the battery still maintains a high capacity, highlighting its excellent rate performance. The distribution of relaxation time (DRT) analysis reveals that the LLZAO buffering layer can enhance the kinetics at the cathode/electrolyte interface. Theoretical calculation further confirms that the strong Zr-O bond formed by Zr doping can stabilize the lattice oxygen and effectively prevent the sulfide solid electrolyte from further electrochemical oxidation, thereby enhancing the interfacial dynamic and stability. These encouraging results provide a new strategy for the practical application of high-energy–density ASSBs, enabling fast charge transfer, extended cycle longevity and enhanced safety.

Tubular-like Nanocomposites with Embedded Cu9S5-MoSx Crystalline-Amorphous Heterostructure in N-Doped Carbon as Li-Ion Batteries Anode toward Ultralong Cycling Stability.

Transition metal sulfides (TMSs) show the potential to be competitive candidates as next-generation anode materials for Li-ion batteries (LIBs) due to their high theoretical specific capacity. However, sluggish ionic/electronic transportation and huge volume change upon lithiation/delithiation remain major challenges in developing practical TMS anodes. We rationally combine structural design and interface engineering to fabricate a tubular-like nanocomposite with embedded crystalline Cu9S5 nanoparticles and amorphous MoSx in a carbon matrix (C/Cu9S5-MoSx NTs). On the one hand, the hybrid integrated the advantages of 1D hollow nanostructures and carbonaceous materials, whose high surface-to-volume ratios, inner void, flexibility, and high electronic conductivity not only enhance ion/electron transfer kinetics but also effectively buffer the volume changes of metal sulfides during charge/discharge. On the other hand, the formation of crystalline-amorphous heterostructures between Cu9S5 and MoSx could further boost charge transfer due to an induced built-in electric field at the interface and the presence of a long-range disorder phase. In addition, amorphous MoSx offers an extra elastic buffer layer to release the fracture risk of Cu9S5 crystalline nanoparticles during repetitive electrochemical reactions. Benefiting from the above synergistic effect, the C/Cu9S5-MoSx electrode as an LIB anode in an ether-based electrolyte achieves a high-rate capability (445 mAh g-1 at 6 A g-1) and superior ultralong-term cycling stability, which delivers an initial discharge capacity of 561 mAh g-1 at 2 A g-1 and its retention capacity after 3600 cycles (376 mAh g-1) remains higher than that of commercial graphite (372 mAh g-1).

A Porous Li-Al Alloy Anode toward High-Performance Sulfide-Based All-Solid-State Lithium Batteries.

Compared to lithium (Li) anode, the alloy/Li-alloy anodes show more compatible with sulfide solid electrolytes (SSEs), and are promising candidates for practical SSE-based all-solid-state Li batteries (ASSLBs). In this work, a porous Li-Al alloy (LiAl-p) anode is crafted using a straightforward mechanical pressing method. Various characterizations confirm the porous nature of such anode, as well as rich oxygen species on its surface. To the best knowledge, such LiAl-p anode demonstrates the best room temperature cell performance in comparison with reported Li and alloy/Li-alloy anodes in SSE-based ASSLBs. For example, the LiAl-p symmetric cells deliver a record critical current density of 6.0mA cm-2 and an ultralong cycling of 5000h; the LiAl-p|LiNi0.8Co0.1Mn0.1O2 full cells achieve a high areal capacity of 11.9 mAh cm-2 and excellent durability of 1800 cycles. Further in situ and ex situ experiments reveal that the porous structure can accommodate volume changes of LiAl-p and ensure its integrity during cycling; and moreover, a robust Li inorganics-rich solid electrolyte interphase can be formed originated from the reaction between SSE and surface oxygen species of LiAl-p. This study offers inspiration for designing high-performance alloy anodes by focusing on designing special architecture to alleviate volume change and constructing stable interphase.

Pyrene-4,5,9,10-tetraone-based covalent organic framework/carbon nanotube composite as sodium-ion cathodes with high-rate capability

Covalent organic frameworks (COFs) have attracted significant interest in the field of rechargeable batteries on account of their unique properties, including robust frameworks, well-defined porosity, abundant redox-active sites, and flexible structure designability. However, the limited active site utilization and low electrical conductivity always bring about poor electrochemical performance, thereby hindering practical applications. Herein, we reported a pyrene-4,5,9,10-tetraone-based covalent organic framework composite (Tp-PTO-COF@CNTs) grown on multi-walled carbon nanotubes via in-situ polycondensation. The Tp-PTO-COF@CNTs with numerous active sites (C=O groups) and strong π-π interaction between CNTs and COFs could accommodate more Na-ions and boost structural stability. Moreover, the existence of 1D CNTs could improve electronic conductivity, which facilitates fast transport of electrons and enhances reaction kinetics. In view of the two synergistic effects, Tp- PTO-COF@CNTs cathode displays an outstanding sodium-ion storage property with high initial capacity of 223.2 mA h/g at 0.1 A/g, remarkable rate capability at as high as 20 A/g, and ultra-long cycling stability (163.0 mA h/g exceeding 5000 cycles at 5 A/g). Furthermore, the ex-situ measurements are proposed to better confirm the role of carbonyl groups as redox-active centers. Such ultra-stable structural advantage might inspire the development of COF cathode materials for sodium-ion batteries.

Mangenese Copper Selenide Nanosheet Arrays Derived from Metal-Organic Frameworks for Efficient Solid-State Asymmetric Supercapacitors

Metal chalcogenide nanostructures, particularly metal selenides, have unique properties, such as high electrical conductivity, large specific surface area, exclusive porous networks, and exceptional electrochemical properties compared to traditional nanostructures.1 2 A novel strategy is proposed to design and fabricate hierarchical Manganese copper selenide nanosheet (MnCuSe NS) arrays from metal-organic frameworks (MOFs). The hierarchical MnCuSe NS arrays can deliver enriched electroactive sites and shorten the ion/electron diffusion pathways. When evaluated as positive electrodes for supercapacitor (SC), the MnCuSe NS electrode displayed remarkable electrochemical properties with ultra-high specific capacity of ≈350.4 mA h g− 1 and an areal capacity of ≈0.94 mA h cm− 2 at a current density of 3 mA cm− 2, exceptional rate capability (≈79.5% of the capacity retention at a higher current density of 50 mA cm− 2), and outstanding cyclic stability (≈95.4 % of capacity retention after 10 000 cycles). Most importantly, the assembled MnCuSe NS//FeMnO/NG solid-state asymmetric SC exhibited a wide operating potential window of 1.6 V with an ultra-high volumetric capacity of ≈2.4 mA h cm− 3 at a current density of 3 mA cm− 2, an excellent energy density of ≈71.6 Wh Kg− 1 at a power density of ≈794 W Kg− 1, and ultra-long cycle life (≈93.4 % of capacity retention after 10 000 cycles). This proposed method provides a general protocol to design and fabricate metal selenide nanosheet arrays with superior electrochemical energy storage properties and exceptional cyclic stability, holding significant potential for future energy storage devices in commercial aspects. Keywords: Hierarchical, Metal-organic frameworks, Metal chalcogenide, Energy density, Asymmetric supercapacitorsReference:(1) Han, J. H.; Kwak, M.; Kim, Y.; Cheon, J. Recent Advances in the Solution-Based Preparation of Two-Dimensional Layered Transition Metal Chalcogenide Nanostructures. Chem. Rev. 2018, 118 (13), 6151–6188. https://doi.org/10.1021/acs.chemrev.8b00264.(2) Karuppasamy, K.; Vikraman, D.; Hussain, S.; Kumar Veerasubramani, G.; Santhoshkumar, P.; Lee, S.-H.; Bose, R.; Kathalingam, A.; Kim, H.-S. Unveiling a Binary Metal Selenide Composite of CuSe Polyhedrons/CoSe2 Nanorods Decorated Graphene Oxide as an Active Electrode Material for High-Performance Hybrid Supercapacitors. Chemical Engineering Journal 2022, 427, 131535. https://doi.org/10.1016/j.cej.2021.131535.