Ultra-stable Cycling Performance Research Articles

Rare Earth Single-Atom Catalysis for High-Performance Li-S Full Battery with Ultrahigh Capacity.

Lithium-sulfur (Li-S) batteries have many advantages but still face problems such as retarded polysulfides redox kinetics and Li dendrite growth. Most reported single atom catalysts (SACs) for Li-S batteries are based on d-band transition metals whose d orbital constitutes active valence band, which is inclined to occur catalyst passivation. SACs based on 4f inner valence orbital of rare earth metals are challenging for their great difficulty to be activated. In this work, we design and synthesize the first rare earth metal Sm SACs which has electron-rich 4f inner orbital to promote catalytic conversion of polysulfides and uniform deposition of Li. Sm SACs enhance the catalysis by the activated 4f orbital through an f-d-p orbital hybridization. Using Sm-N3C3 modified separators, the half cells deliver a high capacity over 600 mAh g-1 and a retention rate of 84.3% after 2000 cycles. The fabricated S/CNTs|Sm-N3C3@PP|Sm-N3C3-Li full batteries can provide an ultra-stable cycling performance of a retention rate of 80.6% at 0.2 C after 100 cycles, one of the best full Li-S batteries. This work provides a new perspective for the development of rare earth metal single atom catalysis in electrochemical reactions of Li-S batteries and other electrochemical systems for next-generation energy storage.

Conformally reactive interphase enables excellent kinetics and cyclability in quasi-solid-state sodium metal battery

The rational design of flexible and robust anode-electrolyte interface is of great significance for extending the cycle life and improving the kinetics performance for sodium metal batteries (SMBs). Herein, a conformally reactive solid-electrolyte interphase (SEI) is constructed through a spontaneous absorption-oligomerization strategy in a quasi-solid-state polymer electrolyte (QSE-T). The polymeric network in the QSE-T system ensures a stable environment with high Na+ transfer number to suppress Na dendrite growth and chemical corrosion. Simultaneously, the reactive SEI is consisted of inorganic NaF and low crosslinked O-B-O and O-B-F segments derived from the 4-trifluoromethylphenylboronic acid (TFPBA) additive, which exhibits lower Na+ diffusion-barriers, and accommodates the ever-changing quasi-solid interface during cycling. Consequently, the NVP||QSE-T||Na cells exhibit ultra-stable cycling performance and high rate capability, with a high initial capacity of 95.1 mAh g−1 at a high rate of 5 C and a capacity retention rate of 86.6 % after 12,000 cycles.

Ternary Mg alloy-based artificial interphase enables high-performance rechargeable magnesium batteries

Rechargeable magnesium batteries (RMBs) provide potential advantages over lithium-ion batteries in terms of high volumetric capacity, natural abundance, and high safety. However, the rational design of high-performance magnesium-based metal anodes compatible with conventional electrolytes is a big challenge for the viability of RMBs. In this work, an in-situ formed ternary alloy-based artificial interphase layer on Mg foil as an anode was successfully prepared through a facile and universal electrodeposition strategy. The Mg-Sn-Bi@Mg anode provides high charge transfer dynamics for Mg deposition and constructs a reduced energy barrier for Mg2+ ions desolvation. Thanks to the unique Mg deposition behaviors, the Mg-Sn-Bi@Mg alloy anode demonstrates a low overpotential of 39.4 mV and a long cycle life of >2000 h. The transfer kinetics for RMBs can be largely improved due to the unique alloying reactions. Density functional theory (DFT) calculations demonstrate that the designed ternary alloy-based artificial interphase layer enables faster Mg2+ ion migration than the bare Mg electrode. Full cells with Mo6S8 cathode also show ultra-stable cycling performance over 2400 cycles at 1C in a conventional all-phenyl complex (APC) electrolyte. This facile interface modification strategy sheds light on the development of advanced RMBs and also provides a promising direction for the design of high-performance Mg-based alloy anodes for high-performance RMBs and beyond.

Facile synthesis of polymer-derived K, Ti co-doped Li4SiO4-based sorbent for efficient and stable post-combustion CO2 capture

Li4SiO4-based sorbent has received considerable attention in the past decade due to its attractive intrinsic merits for post-combustion CO2 capture. To meet the practical applications, the development of Li4SiO4-based sorbent with more higher capture performances by an easy preparation route is desired. In this work, a facile and novel polymer-derived ceramic strategy (PDCs) was used to yield the high-performance Li4SiO4-based sorbent. The phase evolution and microstructure development of Li4SiO4 during the polymer-to-ceramic conversion were investigated. The CO2 capture performances of obtained Li4SiO4 sorbent were studied by comparing with other methods. To further improve its capture performances, Ti(EtO)4-K2CO3 were doped in Li4SiO4, and the enhancement mechanism was surveyed. Results indicate that high-purity Li4SiO4 sorbent with high adsorption properties can be prepared by PDCs route at 700 ℃, and it possessed similar synthesis and adsorption kinetics with the Li4SiO4 prepared by sol–gel method. The 5 mol% Ti doping exhibited a dual enhancement of adsorption capacity and cyclic stability for Li4SiO4 sorbent. Especially, due to the positive synergistic effect of the K, Ti co-doping, the obtained K/5TE-PDCs-Li4SiO4 sorbent showed ultra-high adsorption capacity (0.303 gCO2/gsorbent), ultra-fast adsorption rate (0.219 gCO2/(gsorbent·min)) and ultra-stable cycling performance at a low CO2 concentration (15 vol%). These efficient and stable CO2 capture performances prove the huge potential of polymer-derived K, Ti co-doped Li4SiO4-based sorbent for practical industrial applications.

Facile construction of Cu2-xSe@C nanobelts as anode for superior sodium-ion storage

Transition metal selenides are considered promising electrochemical energy storage materials due to their excellent rate properties and high capacity based on multi-step conversion reactions. However, its practical applications are hampered by poor conductivity and large volume variation for Na+ storage, which resulting fast capacity decay. Herein, a facile metal-organic framework (MOF) derived method is explored to embed Cu2-xSe@C particles into a carbon nanobelts matrix. Such carbon encapsulated nanobelts' structural moderate integral electronic conductivity and maintained the structure from collapsing during Na+ insertion/extraction. Furthermore, the porous structure of these nanobelts endows enough void space to mitigate volume stress and provide more diffusion channels for Na+/electrons transporting. Due to the unique structure, these Cu2-xSe@C nanobelts achieved ultra-stable cycling performance (170.7 mAh/g at 1.0 A/g after 1000 cycles) and superior rate capability (94.6 mAh/g at 8 A/g) for sodium-ion batteries. The kinetic analysis reveals that these Cu2-xSe@C nanobelts with considerable pesoudecapactive contribution benefit the rapid sodiation/desodiation. This rational design strategy broadens an avenue for the development of metal selenide materials for energy storage devices.

High-efficiency electrodeposition of magnesium alloy-based anodes for ultra-stable rechargeable magnesium-ion batteries.

Rechargeable magnesium batteries (RMBs) have attracted much attention because of their high theoretical volumetric capacity and high safety. However, the uneven deposition behavior, harmful corrosion reaction and poor stability of magnesium metal anodes have hindered the practical application of RMBs. Herein, we propose a facile alloy electrodeposition method to construct an artificial layer on an Mg anode. Experimental results show that the polarization of the symmetric magnesium alloy-based (Mg-Sn@Mg and Mg-Bi@Mg) cells is significantly reduced (∼0.05 V) at a current density of 0.1 mA cm-2. The symmetric cells using the prepared Mg alloy anodes exhibited lower voltage hysteresis and ultra-stable cycling performance at a higher density of 1.0 mA cm-2 over 700 h. The in situ optical microscopy study clearly demonstrated that the Mg dendrite formation was successfully retarded by the designed Mg-Sn and Mg-Bi alloy artificial protective layer on Mg anodes. The superiority of Mg-Sn@Mg and Mg-Bi@Mg was further confirmed in full cells using Mo6S8 as the cathode. Compared with the Mo6S8//Mg full cell, the Mo6S8//Mg-Sn@Mg and Mo6S8//Mg-Bi@Mg full cells maintained an ultra-stable electrochemical performance even after 5000 cycles. This proof-of-concept provides a novel scope for the artificial coating layers on Mg anodes prepared by alloy electrodeposition and can be extended to other alloy anodes (i.e. Mg-Cu@Mg and so on). This work provides an avenue for the design of practical and high-performance RMBs and beyond.

Synergetic anion-cation co-doping in Na0.44MnO2 boosting a high-stability and improved-kinetics cathode for sodium ion battery

Tunnel-type manganese-based oxide cathodes of sodium-ion batteries have attracted enormous attentions due to their advantages of low cost, good endurance to the ambient air and superior cycling stability. However, they still suffer from successive phase transitions and sluggish kinetics, which hampers their further practical applications. Herein, we introduce Cu2+ and F− into the typical tunnel material Na0.44MnO2 to improve the abovementioned shortages for the first time. As a result, the ultra-stable cycling performance (capacity retentions of 98.9% after 150 cycles at 120 mA/g and 98.0% after 200 cycles at 360 mA/g) and enhanced Na+ diffusion rate can be achieved thanks to the synergistic effect of anion-cation co-doping. More importantly, with the aid of experiments and theoretical calculations, we unequivocally shed light on the role of Cu2+ and F−, respectively. Besides, the underlying practical value of the optimal case is assessed in the full cell. This work provides a universal perspective for designing oxide cathodes with respectable performance, and paves a new way to promote the practical applications of SIBs.

Pseudocapacitance-Dominated MnNb2 O6 -C Nanofiber Anode for Li-Ion Batteries.

MnNb2 O6 anode has attracted much attention owing to its unique properties for holding Li ions. Unluckily, its application as a Li-ion battery anode is restricted by low capacity because of the inferior electronic conductivity and limited electron transfer. Previous studies suggest that structure and component optimization could improve its reversible capacity. This improvement is always companied by capacity increments, however, the reasons have rarely been identified. Herein, MnNb2 O6 -C nanofibers (NFs) with MnNb2 O6 nanoparticles (~15 nm) confined in carbon NFs, and the counterpart MnNb2 O6 NFs consisting of larger nanoparticles (40-100 nm) are prepared by electrospinning for clarifying this phenomenon. The electrochemical evaluations indicate that the capacity achieved by the MnNb2 O6 NF electrode presents an activation process and a degradation in subsequence. Meanwhile, the MnNb2 O6 -C NF electrode delivers high reversible capacity and ultra-stable cycling performance. Further analysis based on electrochemical behaviors and microstructure changes reveals that the partial structure rearrangement should be in charge of the capacity increment, mainly including pseudocapacitance increment. This work suggests that diminishing the dimensions of MnNb2 O6 nanoparticles and further confining them in a matrix could increase the pseudocapacitance-dominated capacity, providing a novel way to improve the reversible capacity of MnNb2 O6 and other intercalation reaction anodes.

High-performance electroionic artificial muscles boosted by superior ion transport with Ti3C2Tx MXene/Cellulose nanocomposites for advanced 3D-motion actuation

Low-voltage driven electro-ionic soft actuators with large deformation strain are of promising candidate for high-performance artificial muscles, with practical applications in flexible electronics, biomedical assistive devices and soft robotics. However, enhancing the actuation response and long-term stability along with excellent bending properties simultaneously still remain significant challenges. Herein, an elaborate ionically crosslinked nanocomposite membrane, assembled with 1D bacterial cellulous (BC) nanofibers and 2D Ti3C2Tx MXene nanomaterials, is reported to improve constrained ion transport for high-performance electrically activated ionic actuator. The 3D interpenetrating frameworks, arising from the synergistic effects of such combination, not only serve to enhance ion selectivity through the presence of intrinsically negatively charged functional groups but also expand the initially confined pathways, thus diminishing the energy barrier to ion transport. As a result, the integrated superior functionalities of the soft actuator exhibit large bending strain of 0.88 % with the tip displacement of 10.8 mm, ultra-stable cycling performance (>99 % retention for 5 h), and ultrabroad material response range up to 18 Hz under an ultralow voltage exertion of 0.5 V. Furthermore, the demonstration of the prototype soft actuators as actuating tracking beams of 3D-adaptive motion platform for plate deformable mirror shows their potential applications of soft robotics, thereby offering a dependable solution for driving the next generation of sophisticated intelligent systems.

Two-dimensional VSe2/CNT functional materials boosted polysulfide conversion for high stability lithium-sulfur battery

Lithium-sulfur batteries are considered one of the most likely next-generation batteries to be commercialized because of their high theoretical energy density, but severe shuttle effects affect their practical application. Herein, two-dimensional layered vanadium diselenide is combined with carbon nanotubes (2D-VSe2/CNT) to act as advanced sulfur host to suppress the shuttling of lithium polysulfides. 2D-VSe2/CNT possesses sulfiphilic surface and high electrical conductivity, which is beneficial for chemisorption of polysulfides as well as the nucleation and growth of Li2S. In addition, the fast kinetic response is confirmed by the higher current density and the large lithium ion diffusion coefficient. Furthermore, VSe2/CNT/S cathode shows ultra-stable cycling performance with a capacity decay rate of only 0.03% after 500 cycle at 0.5C.

Reconstruction suppressed solid-electrolyte interphase by functionalized metal-organic framework

Lithium metal batteries (LMB) hold the key to unlock the utilization of future technologies with inflating energy consumption demands. However, the long-term cycling performance of LMB under high current density and areal capacity is inferior due to the dendrite growth aggravated by the continuous unnecessary reconstruction induced by instable phases in solid-electrolyte interphase (SEI). Herein, F-functionalized metal-organic framework (MOF), i.e., UIO-66-F4, is employed to enable the enrichment of LiF and suppress the reconstruction of SEI. Moreover, the functionalized MOF can modify the solvation structure of Li+ at the interface, improving the efficiency of Li+ transfer. As a result, an ultra-stable cycling performance for more than 2000 h at 3 mA cm−2 under 6 mAh cm−2 for Li||Li symmetrical cell is achieved, properly covering the capacity range for practical application of LMB. The soft-short risk and the rapid capacity degradation in high-loading Li-S pouch cell are eliminated, benefiting its application as next-generation energy storage system.

Electrochemical Self-Healing Nanocrystal Electrodes for Ultrastable Potassium-Ion Storage.

The unique properties of self-healing materials hold great potential in battery systems, which can exhibit excellent deformability and return to its original shape after cycling. Herein, a Cu3 BiS3 anode material with self-healing mechanisms is proposed for use in ultrastable potassium-ion battery (PIB) and potassium-ion hybrid capacitor (PIHC). Different from the binder design, Cu3 BiS3 anode can exhibit the dual advantages of phase and morphological reversibility, further remaining original property after potassiation/depotassiation and exhibiting ultrastable cycling performance. The reversible electrochemical reconstruction during the continuous charge/discharge processes is beneficial to maintain the structure and function of the material. Furthermore, the conversion reactions during the charge and discharge process produce two advantages: i) suppressing the shuttle effect due to the formation of the heterostructure interface between Cu (111) and Bi (012); ii) Cu can avoid the agglomeration of Bi nanoparticles (NPs), further improving the electrochemical performance and long-cycle stability of the Cu3 BiS3 electrode. As a result, the Cu3 BiS3 electrode not only exhibits a long cycle life in half cells, but also 2000 cycles and 12000 cycles in PIB and PIHC full cells, respectively.

Enabling Multi-electron Reactions in NASICON Positive Electrodes for Aqueous Zinc-Metal Batteries

Sodium superionic conductor (NASICON)-structured compounds with a robust polyanionic framework, e.g., Na3V2(PO4)3, have been considered as promising cathode candidates for rechargeable batteries due to their open 3D structure and high thermal stability. However, their practical implementation in aqueous batteries is hindered by their structural instability during the charge/discharge process. Herein, Na3V2-xCrx(PO4)3 is investigated as a cathode material for aqueous zinc-metal batteries. It is identified that the Cr substitution has a significant effect on improving its rate capability and cycling stability. As a result, the optimal Na3V1.5Cr0.5(PO4)3 electrode delivers an ultra-stable cycling performance (68% capacity retention after 10,000 cycles at 1000 mA g–1). A two-electron reaction mechanism between V4+/V3+ and V5+/V4+ redox couples has been revealed during the electrochemical process for Zn-ion storage. This work verifies the feasibility of multi-electron reactions in NASICON-type cathodes for aqueous zinc batteries and sheds light on designing advanced cathode materials for other aqueous batteries.

Ultrafast synthesis of battery grade graphite enabled by a multi-physics field carbonization

The typical synthesis of graphite requires carbonization at 2800 °C, which consumes a substantial amount of energy. We present a novel, sustainable and cost-effective method for synthesizing high-crystallinity graphite in 13 min at a low temperature of 1100 °C and a multi-physics field (MPF) carbonization coupling with a Ni catalyst. The MPF synergistically benefits from a thermal field, an electric field, and a pressure field in an MPF furnace at the lab scale. Molecular dynamics and differential charge density calculation indicated that the MPF carbonization facilitated exceptional kinetics, and considerably accelerated the breaking of the Ni-metal-catalyzed C-O bonds. The starch-derived graphite anode provided a reversible Li+ storage capacity of 370.7 mAh g−1, matching that of commercial graphite. It also demonstrates exceptional rate performance with a capacity of 103.3 mAh g−1 at an ultra-high current density of 30 A g−1 in diglyme-based Na-ion batteries and ultrastable cycling performance over 10,000 cycles at 2 A g−1. This method will shed some light on how to rapidly fabricate highly crystalline graphite by a energy-saving and low-cost route.

Achieving Stable and Ultrafast Potassium Storage of Antimony Anode via Dual Confinement of MXene@Carbon Framework.

Antimony-based anode materials are recognized for their high potassium storage capacities and appropriate operating potentials. However, the large volume expansion of Sb during the potassiation/depotassiation process, which results in a quick capacity decay, severely limits its practical application in potassium-ion batteries (PIBs). Here, a carbon-coated Sb/MXene heterostructure composite (CSM) is synthesized by adsorption of Sb3+ on MXene nanosheets via Sb-O-Ti bonds followed by carbothermic reduction to construct dual-confined MXene@carbon conductive framework capable of withstanding high volume expansion of Sb and conducive to enabling accelerated electron transfer kinetics. The CSM composite, particularly CSM-700, when configured as an anode for PIBs, realized high capacity (484.4mAh g-1 at 0.1A g-1 ), an ultra-stable cycling performance with a high reversible capacity of 435.9mAh g-1 at 0.1A g-1 after 100 cycles corresponding to a capacity retention rate of 90.0%, and superior rate performance of 323.0mAh g-1 at 1A g-1 . The proposed strategy offers a simple route to construct high-performance Sb-based anodes for advanced PIBs.

Three-dimensional structure S-SnS2/NSG with sulfur vacancies for high-performance lithium-ion batteries

In this contribution, a new three-dimensional (3D) structure of SnS2 with sulfur vacancies (S-SnS2)anchored on the surface of reduced graphene oxide (rGO) was synthesized via a facile solvothermal method. It was found that the addition of glycolic acid promoted the bonding of SnS2 with rGO, and enabling SnS2 to generate sulfur vacancies. As a result, the obtained unique 3D structure facilitated the rapid diffusion of lithium-ion and the S/N-doped rGO (NSG) enhanced the electronic conductivity of the S-SnS2/NSG. In detail, the S-SnS2/NSG as an anode in lithium-ion battery displayed a significant capacity of 1030.2 mA h g−1 at 0.5 A g−1 after 200 cycles. Even at a large current density of 5 A g−1, the S-SnS2/NSG retained an unsurpassed capacity of 790 mA h g−1 after 1000 cycles, demonstrating an ultrastable long cycling performance.

A cyclic organosulfide cathode with ultrastable cycling performance in lithium batteries.

We report a cyclic organosulfide synthesized via a condensation reaction. It can be cycled for 1000 times in half cells. Impressively, it can work with lithiated carbon paper as the anode in ether electrolyte in a full cell. This work shows the promising property of the organosulfide cathode in lithium batteries.

Deciphering the interaction mechanism between copper and polysulfides for enhanced performance and cost-efficiency in quasi-sodium-sulfur batteries

Room-temperature Na-S batteries with Al current collectors face the long-standing challenges of poor cycling performance and rate capability due to the serious sodium polysulfides (NaPSs) shuttling and sluggish reaction kinetics. Here, we demonstrate that a high-performance and low-cost quasi-Na-S battery can be realized by using the Cu@carbon nanotube (CNT) cathode host and unconventional Cu current collector (Cu-CC) in an ether electrolyte. Detailed ex-situ characterizations reveal that the Cu@CNT/S was transformed to NaPSs anchoring on Cu7S4 nanocrystals (~11 nm) during the cycling, forming the NaPS@Cu7S4/CNT cathode with robust sulfur immobilization and enhanced Na+ reaction kinetics. Moreover, the chemical interaction between NaPSs and Cu-CC in situ creates a robust Cu-CC/electrode interface with ultra-small resistance (< 4 Ω), greatly improving the electrode stability and charge transfer kinetics. The synergy of efficient NaPSs trapping and favorable Cu/electrode interface endows the quasi-Na-S battery with a moderate discharge plateau (around 1.2~1.75 V), excellent rate capability (396.9 mAh g-1 at 10 A g-1), and ultra-stable cycling performance (nearly no capacity decay over 1190 cycles). These features make it quite suitable for stable and cost-sensitive grid-scale applications.

An ultrastable sodium-ion battery anode enabled by carbon-coated porous NaTi2(PO4)3 olive-like nanospheres

NaTi2(PO4)3 (NTP) is a promising anode material for sodium-ion batteries (SIBs). It has drawn wide attention because of its stable three-dimensional NASICON-type structure, proper redox potential, and large accommodation space for Na+. However, the inherent low electronic conductivity of the phosphate framework reduces its charge transfer kinetics, thus limiting its exploitation. Therefore, this paper proposes a material with carbon-coated porous NTP olive-like nanospheres (p-NTP@C) to tackle the issues above. Based on experimental data and theoretical calculations, the porous structure of the material is found to be able to provide more active sites and shorten the Na+ diffusion distance. In addition, the carbon coating can effectively improve the electron and Na+ diffusion kinetics. As the anode material for SIBs, the p-NTP@C olive-like nanospheres exhibit a high reversible capacity (127.3 mAh g−1 at 0.1 C) and ultrastable cycling performance (84.8% capacity retention after 10,000 cycles at 5 C). Furthermore, the sodium-ion full cells, composed of p-NTP@C anode and Na3V2(PO4)2F3@carbon cathode, also deliver excellent performance (75.7% capacity retention after 1000 cycles at 1 C). In brief, this nanostructure design provides a viable approach for the future development of long-life and highly stable NASICON-type anode materials.

Nanoarray Architecture of Ultra-Lithiophilic Metal Nitrides for Stable Lithium Metal Anodes.

Lithium metal anode (LMA) is puzzled by the serious issues corresponding to infinite volume change and notorious lithium dendrite during long-term stripping/plating process. Herein, the transition metal nitrides array with outstanding lithiophilicity, including CoN, VN, and Ni3 N, are decorated onto carbon framework as "nests" to uniform Li nucleation and guide Li metal deposition. These transition metal nitrides with excellent conductivity can guarantee the fast electron transport, therefore maintain a stable interface for Li reduction. In addition, the designed multi-dimensional structure of metal nitride array decorated carbon framework can effectively regulate the growth of Li metal during the stripping/plating process. Of note, attributing to the lattice-matching between CoN and Li metal, the composite Li/CoN@CF anode exhibits ultra-stable cycling performance in symmetrical cells (over 4000 h@1mAcm-2 with 1mAhcm-2 and 1000h@20mAcm-2 with 20mAhcm-2 ). The assembled full cells based on Li/CoN@CF composite anode, LiFePO4 or S as cathodes, deliver excellent cycling stability and rate capability. This strategy provides an effective approach to develop a stable lithium metal anode for lithium metal batteries.