Potassium Storage Performance Research Articles

Uniform Bi3Se4 @N-doped carbon spheres as anode for superior lithium and potassium storage performance

Bi3Se4 is a promising anode material for energy storage owing to its merits of layer structure and high specific capacity, however, it usually faces rapid capacity decay and poor rate performances due to the large volume expansion during ion insertion and extraction processes. Herein, Bi3Se4 @N-doped carbon spheres (Bi3Se4 @NC) were fabricated for the first time as anode material for both lithium ion batteries (LIBs) and potassium ion batteries (PIBs). The obtained Bi3Se4 @NC exhibited notable good rate capability (614.4 mAh g−1 at 0.1 A g−1 and 144.5 mAh g−1 even at 20 A g−1) and excellent cycle stability as anode for LIBs. It also displayed preeminent specific capacity of 359.3 mAh g−1 (at 50 mA g−1) and excellent rate capability (achieve capacity as high as 222.4 mAh g−1 at 300 mAh g−1) when used as anode for PIBs. The contribution of the pseudocapacitance capacity and the low resistance of the electrode material contribute to the origin of excellent rate capability. In addition, the potassium ion storage mechanism of Bi3Se4 @NC has been further examined by ex-situ XRD patterns and HRTEM analyses. The above results reveal that the Bi3Se4 @NC composite is a competitive anode material for LIBs and PIBs.

Carbon anode from carbon dots-regulated polypyrrole for enhanced potassium storage

Aiming at the problems of poor cycle stability of carbon-based materials in potassium ion batteries, functionalized nitrogen and sulfur co-doped carbon dots (CDs) are applied to improve the potassium storage performance of electrode materials. In this work, the functionalized CDs are used to regulate the structure and morphology of the polypyrrole in-situ during the polymerization process of pyrrole monomer. Concretely, the original strip-like fibrous polypyrrole can be induced to become bead-like particle with the disappearance of fiber shape, and with the increase of the amount of carbon dots, the active particles increased. Compared with pure polypyrrole derived carbon, the carbon-dot-regulated polypyrrole derived carbon exhibits more excellent cycling performances with a shorter ion transmission and transfer path, more active sites, increased contact area with the electrolyte and improved structural stability. The specific capacity of the carbon anode carbonized from polypyrrole (C-ppy-NSCDs-100) regulated by 100 mg of carbon dots could reach 360.2 mAh g−1 at 0.1 A g−1, showing the application potential of carbon dots in improving electrochemical potassium storage by regulating the morphology of carbon-based materials. Predictably, these unparalleled features of CDs can be expected to inspire more exciting results in potassium-ion energy storage systems.

Insight into Highly Graphitic Hollow Spheres for Superior Potassium Ion Batteries

AbstractGraphite is an attractive anode material for low‐cost potassium‐ion batteries (PIBs), which are highly promising in addressing the urgent demand for large‐scale energy storage systems. However, the large volume variation of graphite during the potassiation/depotassiation may lead to poor long‐term stability, which is unfavorable for commercialization. Herein, highly graphitic hollow spheres (HGHS) are designed by using D‐ribose as the carbon source and Fe‐based catalysts to address these issues, and the effect of graphitization degree on potassium storage performance is explored, which is rarely reported. Fe‐based catalysts can promote graphitization of carbon layer and function as a hard template for manufacturing hollow and spherical architecture. HGHS possess a high porosity, which provides good contact when the liquid electrolyte infiltrates throughout the material. HGHS synthesized with a suitable amount of Fe‐based catalysts display highly graphitic hollow carbon spheres and show a superior potassium storage performance (264 mAh g−1 at 100 mA g−1). The hollow carbon sphere structure and highly graphitic carbon layer endows HGHS with outstanding stability, retaining 87% of the capacity after 500 cycles at 200 mA g−1. This study provides an effective strategy in designing highly graphitic hollow nanostructures for addressing the instability issues of graphite anode in PIBs.

KOH-treated mesocarbon microbeads used as high-rate anode materials for potassium-ion batteries

AbstractGraphite is one of the most promising anode materials for potassium-ion batteries (PIBs) due to its low cost and stable discharge plateau. However, its poor rate performance still needs to be improved. A novel graphitic anode was designed from commercial mesocarbon microbeads (MCMBs) by KOH treatment. Using limited oxidation and slight intercalation, the interlayer spacing of graphitic layers on the surface of the MCMBs was increased, causing the K+ diffusion rate to be significantly improved. When this modified material was combined with carboxymethyl cellulose as a binder (79.2%) and used as a PIB anode, it had a high plateau capacity below 0.25 V (271 mAh g−1), superior rate capability (160 mAh g−1 at 1.0 A g−1), excellent cycling stability (about 184 mAh g−1 after 100 cycles at 0.1 A g−1), and a high initial coulombic efficiency. This work provides a simple strategy to prepare graphitic materials with an excellent potassium storage performance.

Zeolitic imidazolate framework-derived ZnO polyhedrons wrapped by Co nanoparticle embedded in N-doped carbon for high-performance lithium and potassium storage

Metal oxides are considered as promising anodes for alkali-ion batteries due to their high theoretical capacity and moderate volume expansion. However, they still suffer from the low electrical conductivity and capacity decay, resulting poor rate capability and cyclic stability. In this work, core-shell ZnO polyhedrons coated by Co nanoparticle embedded in N-doped carbon (ZnO@Co/NC) were prepared via a convenient route using zeolitic imidazolate frameworks as precursors. The unique structural design not only synergistically forms a three-dimensional conductive network to promote the transfer and storage of Li+/K+ ions, but also restrains the volume changes of ZnO polyhedron during repeated lithiation/potassiation processes, contributing to enhanced lithium and potassium storage performances. The ZnO@Co/NC anode delivers 458.3 mAh g−1 after 1000 cycles at an ultrahigh current density of 10 A g−1 with a capacity retention of 95% for LIBs, and remains 181.5 mAh g−1 after 1000 cycles at 200 mA g−1 with 84% retention for KIBs. When coupled with commercial LiFePO4 cathode, the full cell delivers a capacity of 140.6 mAh g−1 after 250 cycles at 1 A g−1. This work not only shows the promising potential ZnO-based materials for long-term and high-rate lithium-ion batteries, but also gives an insight into the design of ZnO-based anodes for potassium storage.

Construction of MoS2-ZnS@C Heterostructures by Multiple Organic Framework Combination for Fast and Stable Sodium/Potassium Storage

The establishment of three-dimensional structures, carbon coating, and proper defects is an effective strategy to improve electrochemical performance of molybdenum sulfide. In this work, carbon-coated MoS2-ZnS (MoS2-ZnS@C) heterostructures were constructed by treating the MOF precursor with a one-step sulfurization/carbonization strategy. The MoS2-ZnS@C heterostructures not only introduce abundant C–S–C and C–N bonds which contribute to ion storage with enhancive active sites but also effectively accelerate ion diffusion and reaction kinetics. The corresponding reaction mechanism was revealed via XRD and HR-TEM tests. The anode of MoS2-ZnS@C heterostructures shows outstanding rate capability (309 mAh g–1 at 10 A g–1) and long cycle stability (343 mAh g–1 after 1200 cycles at 5 A g–1) in sodium-ion batteries (SIBs). Meantime, the MoS2-ZnS@C heterostructure anode also exhibits enhanced potassium storage performances, delivering a superior rate capability (80 mAh g–1 at 5 A g–1) and superior long cycle performance (297 mAh g–1 after 100 cycles at 0.5 A g–1). In addition, a high specific capacity of 270 mAh g–1 is achieved at 1 A g–1 in a full cell made up of MoS2-ZnS@C/ether-based electrolyte/Na3V2(PO4)3. The construction of heterostructures for improving the electrochemical performance can also be applicable to other battery material fields.

Templated synthesis of imine-based covalent organic framework hollow nanospheres for stable potassium-ion batteries

Covalent organic frameworks (COFs), as highly tunable porous crystalline materials, have promising applications in potassium-ion batteries (PIBs) due to their abundant charge carrier transport channels and excellent structural stability. However, the excessive stacking of interlayer electron clouds makes it difficult to expose internal active sites. Strategies to design functional COFs with controllable morphology and copious active sites are promising but still challenging. Herein, by utilizing the condensation between 1,3,5-triformylbenzene (TFB) and p-phenylenediamine (PPD) and using amino-modified SiO2 nanospheres as templates, we synthesize core-shell NH2-SiO2@TP-COF. Through NaOH etching of NH2-SiO2@TP-COF, we obtain imine-based TP-COF hollow nanospheres, which shows excellent potassium storage performance when applied to the anode for PIBs. Ex-situ analysis and density functional theory calculations reveal that CN groups and benzenes are active sites for K+ storage.

Multilayer structure covalent organic frameworks (COFs) linking by double functional groups for advanced K+ batteries

Covalent organic frameworks (COFs) are regarded as the potential and promising anode materials for potassium ion batteries (PIBs) on account of their robust and porous crystalline structure. In this work, multilayer structural COF connected by double functional groups, including imine and amidogent through a simple solvothermalprocess, have been successfully synthesized. The multilayer structure of COF can provide fast charge transfer and combine the merits of imine (the restraint of irreversible dissolution) and amidogent (the supply of more active sites). It presents superior potassium storage performance, including the high reversible capacity of 229.5 mAh g−1 at 0.2 A g−1 and outstanding cycling stability of 106.1 mAh g−1 at the high current density of 5.0 A g−1 after 2000 cycles, which is superior to the individual COF. The structural advantages of the covalent organic framework linking by double functional groups (d-COF) can develop a new road for that COF anode material for PIBs in further research.

Molten Salt-Assisted Construction of Hollow Carbon Spheres with Outer-Order and Inner-Disorder Heterostructure for Ultra-Stable Potassium Ion Storage.

The central goal of high-performance potassium ion storage is to control the function of the anode material via rational structural design. Herein, N- and S-doped hollow carbon spheres with outer-short-range-order and inner-disorder structures are constructed to achieve highly efficient and ultra-stable potassium ion storage using a low-temperature molten salt system. The ultrathin carbon walls and uniform mesoporous as well as unique heterostructure synergistically realize significant potassium storage performance via facilitating rapid diffusion of potassium ions and alleviating substantial volume expansion. Furthermore, as the anode of a potassium ion battery, the as-prepared MSTC electrode demonstrates a state-of-the-art cycling capability of 221.3 mAh g-1 at 1 A g-1 after 20,000 cycles. The assembled potassium ion hybrid capacitor device demonstrates a high energy of 157 Wh kg-1 at 956 W kg-1 and excellent reversibility at a current density of 5.0 A g-1 after 20,000 cycles with 82.7% capacity retention. Accordingly, our work provides new ideas for designing advanced carbon anode materials and understanding the charge storage mechanism in potassium ion battery, as well as constructing high energy-power density potassium-ion hybrid capacitors (PIHCs).

Bi@Bi2O3 anchored on porous graphene prepared by solvothermal method as a high-performance anode material for potassium-ion batteries

To enhance potassium storage performance of graphene, in situ formed electroactive bismuth nanoparticles were introduced into the porous graphene. The Bi@Bi2O3/graphene composites, which possess the special microstructure that Bi nanoparticles are coated by Bi2O3 and attached to the porous graphene, was synthesized via an environmental-friendly and simple solvothermal method combined with high-temperature sintering under inert environment using graphene oxide, BiCl3 and ethanol as raw materials. Benefiting from the special microstructure and synergistic effect of nano-bismuth particles and graphene, Bi@Bi2O3/graphene composites display better electrochemical performance than graphene. Between 0.01 and 3.0 V (vs K+/K), the electrode was galvanostatically discharged/charged at 100 mA g−1 and the optimal Bi@Bi2O3/graphene composite (Bi@Bi2O3/G-50) has large initial charge capacity (886.4 mAh g−1), which is significantly larger than the theoretic capacities of Bi (385 mAh g−1) and graphene (279 mAh g−1), and after 100 cycles, the high remaining charge capacity of 466.4 mAh g−1 for Bi@Bi2O3/G-50 was obtained. While the remaining charge capacity of graphene is only 112 mAh g−1 after 100 cycles. When electrode cycled at high current density of 800 mA g−1, the initial charge capacities of Bi@Bi2O3/G-50 and graphene are 294.1 and 130 mAh g−1, respectively, and the corresponding remaining capacities are 179.1 and 67.1 mAh g−1, respectively. The results imply that the introduction of high-capacity electroactive materials and the design of special microstructures are effective strategies to significantly improve the potassium storage performance of carbon-based anode materials for potassium-ion batteries.

Graphene supported FeS2 nanoparticles with sandwich structure as a promising anode for High-Rate Potassium-Ion batteries

Pyrite FeS2 now emerges as a promising anode for potassium-ion batteries (PIBs) due to its low cost and high theoretical capacity. However, the significant volume expansion, low electrical conductivity, and the ambiguous mechanism related to potassium storage severely hinder its development for PIBs anodes. Herein, FeS2 nanostructures are skillfully dispersed on the graphene surface layer by layer (FeS2@C-rGO) to form a sandwich structure by using Fe-based metal organic framework (Fe-MOF) as precursors. The unique structural design can improve the transfer kinetics of K+ and effectively buffer the volume expansion during cycling, thereby enhancing the potassium storage performance. As a result, the FeS2@C-rGO delivers a high capacity of 550 mAh/g at a current density of 0.1 A/g. At a high rate of 2 A/g, the capacity can maintain 171 mAh/g even after 500 cycles. Moreover, the electrochemical reaction mechanism and potassium storage behavior are revealed by in-situ X-ray diffractionand density functional theory calculations. This work not only provides a novel insight into the structural design of electrode materials for high-performance PIBs, but also proposes a valuable understanding of the potassium storage mechanism of the FeS2-based anode.

Carbon layer-confined MoS2/Ni3S2 heterostructure with enhanced sodium and potassium storage performance

MoS2/Ni3S2@C shows excellent sodium/potassium storage performance, which is due to carbon layer-confined heterostructure, creating more sodium/potassium storage sites, shortening ions diffusion path and relieving the volume change of the material.

Research on the Preparation and Potassium Storage Performance of F, N Co-doped Porous Carbon Nanosheets

Research on the Preparation and Potassium Storage Performance of F, N Co-doped Porous Carbon Nanosheets

Research on carbon-based and metal-based negative electrode materials via DFT calculation for high potassium storage performance: a review

The key R&D concern in the domain of new energy in recent years has been the large-scale development of electrochemical energy storage. However, the steep increase in pricing has constrained the further expansion of lithium-ion batteries, primarily due to the ongoing depletion of their scarce lithium supplies. A potential candidate material at the moment is the potassium-ion battery (KIB), which has an anode made of carbon and/or an alloy and rich reserves, offering an excellent theoretical capacity and ideal working voltage. More significant advancements are still required to achieve long life and high energy density, despite the fact that some significant breakthroughs have been reported. The most recent findings from research on carbon-based [graphite, hard carbon (HC), and nanoporous carbon] and alloy-based (mainly including Sb, Sn, P, and its compounds) anodes for KIBs are compiled in this document. Numerous simulations at the atomic level based on particular chemical interactions, phase transitions, ion/electron transport dynamics, and conduction band spin utilizing density functional theory (DFT) calculations have been conducted to thoroughly investigate the storage mechanism of K+ on various electrode materials. Moreover, this paper examined contemporary structural modification techniques used in carbon- and alloy-based anode electrode materials and applied DFT calculations to confirm the advancement of its thorough tests. To promote the manufacturing of rechargeable KIBs, the challenges and potential of KIBs were also explored in future research.

Controllable engineering of intrinsic defects on carbon nanosheets enables fast and stable potassium storage performance

Defect-enriched carbon nanomaterials possess high potassium storage capacity and rapid ion transport capability; nevertheless, their rate performance is restricted by the deteriorated electronic conductivity induced by over-broken sp2-C conjugated structure. Herein, intrinsic defect-enriched carbon nanosheet (DCS) with controllable defect density is reported for the high-efficiency anode of potassium-ion batteries (PIBs). The DCS constructed by internal sp2-C configuration and external sp3-C defects can ensure good electron transport ability and afford abundant active sites for K+ storage. As PIBs anode, DCS-24 obtained by ball-milling for 24 h with optimized defect density delivers a high specific capacity of 270.9 mAh g−1 at 0.5 C, an excellent rate performance (189 mAh g−1 at 10 C), as well as long cycle durability (255.1 mAh g−1 over 3000 cycles at 1 C). Electrochemical results and density functional theory simulations indicate that the intrinsic defects of carbon materials improve the capacitive K+ storage capacity, speed up the K+ diffusion, and lower the K+ adsorption energy.

Russian-Doll-Like Porous Carbon as Anode Materials for High-Performance Potassium-Ion Hybrid Capacitors.

Pore-structure design with the sophisticated and pragmatic nanostructures still remains a great challenge. In this work, porous carbon with Russian-doll-like pores rather than traditional single modal is fabricated via a boiling carbonization approach, accompanied by K+ -pre-intercalation. The most important internal factor is that alkali can penetrate into the stereoscopic space of layered Malonic acid dihydrazide and the confinement effect leads to the in-depth development of different dimensional pore structures. The oxygenated and nitrogenated surface guarantees the K+ intercalation behavior. Benefiting from their open framework and enlarged interlayer spacing, K+ -pre-intercalated porous carbon with Russian-doll-like pores (denoted as KPCRPs) as anode material exhibits promising potassium storage performance. The assembled KPCRP//activated carbon potassium-ion hybrid supercapacitor in 30m CH3 COOK displays a high energy density of 157.29Whkg-1 , an ultrahigh power output of 14kWkg-1 , and a long cycling life (99.58% capacity retention after 10000 cycles), highlighting the superiority of Russian-doll-like pore structure. This work sheds light on the designing of 3D pores structure, especially for multimodal pore architectures.

Self-Standing Soft Carbon-Coated MoS2 Nanofiber Film Anode for Superior Potassium Storage

The poor electronic conductivity and large volume expansion effect of MoS2 limit its application in potassium-ion batteries (PIBs). In addition to exploring effective modification methods, it is also necessary to build a new self-standing electrode system to improve its energy density. In this work, based on the potassium storage advantages and disadvantages of MoS2 and carbon nanofibers, we have successfully prepared a self-standing soft carbon-coated MoS2 nanofiber film electrode without any additives or metal collectors. As for the application in PIBs, it exhibits excellent rate performances (about 93 mA h g−1 at the current density of 10 A g−1), and superior long-term cycling stability performances (a high-capacity retention of ~75% after 1800 cycles at the current density of 1 A g−1). The enhanced potassium storage performance can be attributed to the unique self-standing nanofiber film architectures.

Design of free-standing porous carbon fibers anode with high-efficiency potassium-ion storage

Designing porous structures is emerging as a promising approach to prominently improve the potassium storage performance of carbonaceous materials. In this work, we design free-standing porous carbon fibers (PCF) by electrospinning for highly potassium-ion storage. With the introduction of Zn in the electrospinning precursor, the PCF was obtained after the evaporation of Zn during the heat treatment. After bending and folding, the free-standing PCF also presents excellent flexibility. As the free-standing anode for potassium-ion battery (KIB), it is found that the PCF presents an enhanced potassium-ion storage performance with a reversible specific capacity of 256 mAh/g after 80 cycles at 50 mA g−1. Even at the current density of 1 A/g, our PCF still remains a high reversible specific capacity of 149 mAh/g after 3300 cycles for KIBs. According to the density functional theory calculation and finite element analysis, we find that K-ions can also inset into the carbon layer during the fully potassiation state for the porous structure of PCF. In addition, due to the strong adsorption characteristics of K-ions, the porous structure of porous carbon fibers also can accommodate K-clusters in the pore defects. The common effects of the K-intercalation and K cluster contribute to the improvement of the K-ion storage performance of porous carbon fibers.

Antimony anchored in MoS2 nanosheets with N-doped carbon coating to boost potassium storage performance

Potassium ions batteries (PIBs) have been considered as promising energy storage systems owning to potassium rich natural abundances. However, the difficult reaction kinetics and poor cycling of electrode restrict the further development of PIBs. In this work, antimony anchored in MoS2 nanosheets with N-doped carbon coating (Sb/MoS2/NCs) are prepared and evaluated as anode for PIBs. In the unique Sb/MoS2/NCs structure, the volume expansion of Sb particles could be effectively buffered by the around MoS2 structure. The defects in MoS2 nanosheets provide more electrochemical reaction sites for sufficient K+ insertion/extraction. Furthermore, the N-doped carbon can further accommodate the volume expansion and improve the electronic conductivity of Sb/MoS2/NCs composites. Due to the above advantages, the Sb/MoS2/NCs anode delivers a capacity of 235 mAh/g at 50 mA/g after 78 cycles. This work provides a prospective strategy to design advanced anode materials for PIBs using MoS2 and antimony composites.

Electrochemical activity regulating by strain control to achieve high-performance potassium-ion-based dual-ion battery

Potassium dual ion batteries (K-DIBs) are attractive candidates for grid-scale energy storage. However, the poor rate capability/cycle stability and low energy density seriously impede their practical implementation. Herein, a method to realize electrochemical activity tuning for K-ion storage by regulating the interlayered strain of hydrogen titanate is proposed. Volume expansion, caused by the alloying reaction between Na+ and pre-imbedded Sn-ions in hydrogen titanate, triggers the widening of interlayer spacing and partial distortion of Ti-O slabs, and lattice tension of 24% is observed in the designed anode. Revealed by DFT and BVLS calculations, fully Na+ insertion between Ti-O layers would generate strong Coulomb repulsion with K+, increasing the diffusion barrier of K+. Partial Na+ removal could reduce the Coulomb repulsion and the Na-activated anode with 2/3 Na insertion per formula unit delivers the lowest percolation energies for K+ migration. Moreover, Na-based SEI with organics dominated on the outer layer and inorganics on the inner layer is more uniform and thinner than that of K-based SEI. These merits result in a 322% improvement in potassium storage performance. When used as an additive-free anode for K-DIBs, the K-DIBs can deliver a reversible capacity of 96 mAh g−1 and work stably for 2000 cycles.