Anode For Potassium-ion Batteries Research Articles

Nitrogen-doped carbon with antimony nanoparticles as a stable anode for potassium-ion batteries

Potassium-ion batteries are considered promising alternatives to lithium-ion batteries (LIBs) because they have a lower redox K+/K potential, a lower Stokes radius, abundant raw materials, and economic benefits. However, K has a larger ionic radius than Li, which may limit the diffusion of K ions into electrodes and cause poor electrode rate capability and cycling stability. In this study, N-doped C and Sb (NC@Sb) composites were synthesised using a facile and cost-effective method of carbonisation and ball milling. The NC@Sb composites had an interconnected and highly porous structure, which was formed by the release of gases such as CO, H2O, CO2, and NH3 during carbonisation. Additionally, NC@Sb is a promising anode owing to the synergistic effects of the high specific capacity of Sb and the good cycling stability of NC. In particular, the NC@Sb composite that contained 10 wt% Sb (NC@Sb10) exhibited a high reversible capacity of 264 mAh g−1 after 100 cycles at a specific current of 200 mA g−1. Furthermore, the NC@Sb10 electrode maintained 85% of its initial capacity at a high specific current of 1 A g−1 even after 500 discharge–charge cycles. The excellent electrochemical performance of the NC@Sb composite is mainly attributed to the stable embedding of the Sb nanoparticles in the porous and electrically conductive NC matrix, which can buffer Sb stress and provide a pathway for the penetration of the electrolyte and K ions.

Two-dimensional carbon rich titanium carbide (TiC3) as a high-capacity anode for potassium ion battery

In recent years, two-dimensional (2D) materials, particularly MXenes such as titanium carbide, have gained significant interest for energy storage applications. This study explores the use of potassium-adsorbed TiC3 nanosheets as potential anode materials for potassium ion batteries (KIBs), utilizing first-principles calculations. The investigated electronic, mechanical, and thermal properties of TiC3 demonstrate its suitability as an anode material. The incorporation of potassium into the host material enhances electronic conductivity while maintaining a stable layered structure. Our findings reveal promising adsorption behavior of potassium in TiC3, leading to a high theoretical specific capacity of 958 mAh/g, coupled with a low energy barrier of 0.19 eV for potassium migration, which is indicative of superior electrochemical performance. Moreover, despite the high potassium content, the electrode material shows limited volume expansion of 11.3 %, suggesting good cyclability. Additionally, the equilibrium distance between potassium and TiC3, measured at 3.11 Å, exceeds that of lithium and TiC3 (2.56 Å), potentially augmenting the material’s flexibility. Consequently, TiC3 emerges as a promising candidate for KIB anode materials.

Design of heterostructured hydrangea-like FeS2/MoS2 encapsulated in nitrogen-doped carbon as high-performance anode for potassium-ion capacitors

The means of structural hybridization such as heterojunction construction and carbon-coating engineering for facilitating charge transfer and electron transport are considered viable strategies to address the challenges associated with the low rate capability and poor cycling stability of sulfide-based anodes in potassium-ion batteries (PIBs). Motivated by these concepts, we have successfully prepared a hydrangea-like bimetallic sulfide heterostructure encapsulated in nitrogen-doped carbon (FMS@NC) using a simple solvothermal method, followed by poly-dopamine wrapping and a one-step sulfidation/carbonization process. When served as an anode for PIBs, this FMS@NC demonstrates a high specific capacity (585 mAh g−1 at 0.05 A/g) and long cycling stability. Synergetic effects of mitigated volume expansions and enhanced conductivity that are responsbile for such high performance have been verified to originate from the heterostructured sulfides and the N-doped carbon matrix. Meanwhile, comprehensive characterization reveals existence of an intercalation-conversion hybrid K-ion storage mechanism in this material. Impressively, a K-ion capacitor with the FMS@NC anode and a commercial activated carbon cathode exhibits a superior energy density of up to 192 Wh kg−1, a high power density, and outstanding cycling stability. This study provides constructive guidance for designing high-performance and durable potassium-ion storage anodes for next-generation energy storage devices.

Boosting Potassium Adsorption and Diffusion Performance of Carbon Anodes for Potassium-Ion Batteries via Topology and Curvature Engineering: From KT-Graphene to KT-CNTs.

We propose a two-dimensional carbon allotrope (named KT-graphene) by incorporating kagome and tetragonal lattices consisting of trigonal, quadrilateral, octagonal, and dodecagonal rings. The introduction of non-hexagonal rings can give rise to the localized electronic states that improve the chemical reactivity toward potassium, making KT-graphene a high-performance anode material for potassium-ion batteries. It shows a high theoretical capacity (892 mAh g-1), a low diffusion barrier (0.33 eV), and a low average open-circuit voltage (0.51 V). The presence of electrolyte solvents is propitious to boost the K-ion adsorption and diffusion capabilities. Moreover, one-dimensional nanotubes (KT-CNTs), rolled up by the KT-graphene sheet, are metallic regardless of the tube diameter. As the curvature increases, KT-CNTs exhibit significantly increased surface activity, which can promote the electron-donating ability of K. Furthermore, the curvature effect greatly enhances the efficiency of K diffusion on the inner surface compared to that on the outer surface.

A synthesis strategy of 3D carbon nanosheet anode with adsorption/intercalation-filling hybrid mechanism for high-performance sodium/potassium-ion batteries

Hard carbons are significant in sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). However, the structural defects of hard carbons lead to poor rate performance and cycling stability, which need further improvement. The waste cooking oil was used as the precursor to synthesize 3D carbon nanosheets (NWCOC) with amino nitrogen functional groups, multi-layered pores, and expanded interlayer spacing. The excellent electrochemical properties of NWCOC were investigated and it was demonstrated that NWCOC can significantly improve the adsorption of Na+/K+ on hard carbons, substantially enhancing the embedding/de-embedding of Na+/K+, reducing the diffusion distance of ions and electrons, and improving their adaptability to volume changes. In situ XRD and Raman characterization reveal that the Na storage mechanism of NWCOC is mainly based on adsorption/intercalation-filling. Combined with density functional theory, it is shown that the porous structures doped with nitrogen have a greater propensity for ion adsorption, resulting in increased ion capture and storage. As expected, NWCOC650 exhibits high capacities of 489.4 and 388.3 mAh/g in SIBs and PIBs. NWCOC650 displays superior performance in the Na3V2(PO4)3/NWCOC650 full cell, achieving a capacity of 107.84 mAh/g. This work presents a new perspective on the synthesis and mechanisms of high-performance anodes for SIBs and PIBs.

Needle coke anodes for potassium-ion batteries: Storage mechanism and interfacial evolution in soft carbon

Needle coke has attracted much attention as soft carbon anode material for potassium-ion batteries (PIBs) owing to its high crystallinity and conductivity. However, limited research has been conducted on the storage mechanism and the functional and structural evolution of the solid electrolyte interphase (SEI) in ester and ether based electrolytes. This work investigates the potassium ion storage mechanisms of soft carbon anodes in three electrolytes: KPF6 EC/DEC, KPF6 DME, and KFSI DME, and reveals that K+ stored in the KPF6 EC/DEC electrolyte could be through an “adsorption-intercalation” mechanism. Whereas K+ stored in the DME-based electrolytes is believed to undergo a “co-intercalation/adsorption-intercalation” process. Interfacial analyses indicate that the SEI formed in the EC/DEC electrolyte inhibits co-intercalation of potassium ion and solvent, which preserves sufficient space to accommodate potassium ion. Conversely, the [K-DME]+ solvation co-intercalation in DME-based electrolytes compromises the structural integrity, and results in a persistent capacity decline. This work offers novel insights into potassium ion storage in ester and ether-based electrolytes, and provides theoretical support for the fabrication of high-performance soft carbon anodes.

Molecular structure regulation of FCCs enabling N/S co-doped hollow amorphous carbon with enlarged interlayer spacing and rich defects for superior potassium storage

Constructing high-performance and low-cost carbon anodes for potassium-ion batteries (PIBs) is highly desirable but faces great challenges. In this study, we present a novel approach to fabricating N/S co-doped hollow amorphous carbon (LNSHAC) for superior potassium storage through a template-assisted molecular structure regulation strategy. By tailoring a 3D crosslinked aromatics precursor from fluid catalytic cracking slurry (FCCs), the LNSHAC features a N/S co-doped hollow structure with enlarged interlayer spacing of up to 0.405 nm and rich defects. Such unique microstructure offers fast transport channels for K-ion intercalation/deintercalation and provides more active sites, leading to boosted reaction kinetics and potassium storage capacity. Consequently, the LNSHAC electrode delivers an impressive reversible capacity (466.2 mAh g−1 at 0.1 A/g), excellent rate capability (336.3 mAh g−1 at 2 A/g), and superior cyclic performance (256.9 mAh g−1 after 5000 cycles at 5 A/g with admirable retention of 76.9 %), standing out among the reported carbon-based anodes. When KFeHCF is employed as the cathode, the LNSHAC-based K-ion full cell exhibits a high reversible capacity of 176.6 mAh g−1 at 0.1 A/g and excellent cyclic stability over 200 cycles. This work will inspire the development and application of advanced carbon-based materials for potassium electrochemical energy storage.

GeV4S8: a Novel Bimetallic Sulfide for Robust and Fast Potassium Storage.

Potassium-ion batteries (PIBs) have attracted much attention due to their low production cost and abundant resources. Germanium is a promising alloying-type anode with a high theoretical capacity for PIBs, yet suffering significant volume expansion and sluggish potassium-ion transport kinetics. Herein, a rational strategy is formulated to disperse Ge atoms into transition metal V-S sulfide frameworks to form a loosely packed and metallic GeV4S8 medium. The theoretical prediction shows that GeV4S8 is conducive to the adsorption and diffusion of K+. The V-S frameworks provide fast ion/electron diffusion channels and also help to buffer the volume expansion during K+ insertion. In situ and ex situ characterizations manifest that KGe alloy clusters are constrained and dispersed by potassiated VS2 topological structure during discharging, and revert to the original GeV4S8 after charging. Consequently, as a novel anode for PIBs, GeV4S8 provides a high specific capacity of ≈400mAhg-1 at 0.5C, maintaining 160mAhg-1 even at 12.5C and ≈80% capacity after 1000 cycles at 5C, superior to most of the state-of-the-art anode materials. The proposed strategy of combining alloy and intercalation dual-functional units is expected to open up a new way for high-capacity and high-rate anode for PIBs.

Pre-bonded hybrid carbon materials with stable structure as anode for potassium-ion batteries

Pre-bonded hybrid carbon materials with stable structure as anode for potassium-ion batteries

Nanopore design of sulfur doped hollow carbon nanospheres for superior potassium-ion battery anodes

Nanopore design of sulfur doped hollow carbon nanospheres for superior potassium-ion battery anodes

Unlocking the potential of ultra-thin two-dimensional antimony materials: Selective growth and carbon coating for efficient potassium-ion storage

Antimony-based anodes have attracted wide attention in potassium-ion batteries due to their high theoretical specific capacities (∼660 mA h g−1) and suitable voltage platforms. However, severe capacity fading caused by huge volume change and limited ion transportation hinders their practical applications. Recently, strategies for controlling the morphologies of Sb-based materials to improve the electrochemical performances have been proposed. Among these, the two-dimensional Sb (2D-Sb) materials present excellent properties due to shorted ion immigration paths and enhanced ion diffusion. Nevertheless, the synthetic methods are usually tedious, and even the mechanism of these strategies remains elusive, especially how to obtain large-scale 2D-Sb materials. Herein, a novel strategy to synthesize 2D-Sb material using a straightforward solvothermal method without the requirement of a complex nanostructure design is provided. This method leverages the selective adsorption of aldehyde groups in furfural to induce crystal growth, while concurrently reducing and coating a nitrogen-doped carbon layer. Compared to the reported methods, it is simpler, more efficient, and conducive to the production of composite nanosheets with uniform thickness (3–4 nm). The 2D-Sb@NC nanosheet anode delivers an extremely high capacity of 504.5 mA h g−1 at current densities of 100 mA g−1 and remains stable for more than 200 cycles. Through characterizations and molecular dynamic simulations, how potassium storage kinetics between 2D Sb-based materials and bulk Sb-based materials are explored, and detailed explanations are provided. These findings offer novel insights into the development of durable 2D alloy-based anodes for next-generation potassium-ion batteries.

A red phosphorus/mesoporous carbon anode for potassium-ion storage

Red phosphorus/mesoporous carbon (RP/CMK-3) composite was fabricated by a facile ultrasonic treatment and freeze-drying approach. As the anode for potassium-ion batteries, RP/CMK-3 with the weight ratio of 2:1 between RP and CMK-3 exhibits high capacities of 192.8 mAh g−1 at 200 mA g−1 and 232.7 mAh/g after 100 cycles at 50 mA g−1. Such a good K+ storage behavior can be attributed to small-size RP particles combined with CMK-3 through P-C bonds, which not only provide a feasible conductive network but also suppress the volume change of RP during repeated potassiation/de-potassiation processes.

Encapsulation of CoS2 nanoparticles in bamboo-like carbon nanotubes as advanced potassium-ion batteries anodes

Transition metal sulfides (TMSs) have been widely investigated as anode materials for potassium ion batteries (PIBs) due to their high theoretical capacity. However, the intense volume change of TMSs in the process of charge/discharge will lead to the destruction of material structure and the decrease of potassium storage performance. Herein, CoS2/CNTs composites are prepared by carbonization and in-situ vulcanization, and the CoS2 nanoparticles are encapsulated in bamboo-like carbon nanotubes. The unique structure can buffer the volume change during charge/discharge, which is responsible for the strong structural stability and remarkable electrochemical storage performance of the composite. When assembled as PIBs half-cell, the CoS2/CNT-600 composite exhibits excellent rate performance (303.7 mAh g−1 at 2000 mA g−1) and favorable cycling stability (325.7mAh g−1 at 100 mA g−1 after 500 cycles). In addition, the successful assembly of the full cell validates the practical application prospects of CoS2/CNT-600 electrodes.

3D Micro‐Flower Structured BiFeO3 Constructing High Energy Efficiency/Stability Potassium Ion Batteries Over Wide Temperature Range

AbstractThe fatty K+ ion calls for suitable host materials to meet the requirement for high safety and long‐term stability of potassium‐ion batteries (PIBs) to rival lithium‐ion batteries, thus anode materials possessing high capacity, high stability, and well‐defined plateaus involving favorable working voltage (≈0.5 V) have always been desired. Here, a 3D BiFeO3 with micro‐flower structure (BFO‐MF) constructed by nanosheets is proposed as an anode for PIBs. Density functional theory calculations evidence that the intrinsically favorable affinity and diffusion for K+ ion render fast electrochemical kinetics and attenuated voltage‐hysteresis, and electrochemical measurements indicate that the stable 3D structure of BFO‐MF enables to achieve impressive performances including a high capacity of 606 mAh g−1, flat plateaus at ≈0.5 V, stable performances for 5000 cycles at 500 mA g−1, and 500 cycles at 100 mA g−1 upon −20 °C. In situ and ex situ characterizations definitely elucidate the conversion and alloy/dealloy mechanism. The satisfying features of BFO‐MF anode ensure full‐cells to achieve excellent cyclic performances, and a high energy efficiency retention rate of ≈98.2% for the cathode, with energy density/power density output up to 177.1 Wh kg−1/2152.8 W kg−1, respectively. This work can provide new insights for developing advanced anodes for PIBs.

Chemically bonded MXene/SnSe2 composite with special structural transformation as a high-performance anode for lithium and potassium ions battery

Sn-C bonding coupled MXene/SnSe2 composite with SnSe2 nanosheets vertically coating on the MXene surface was prepared successfully by the solvothermal method, in which MXene matrix etched separately by HF and LiF/HCl was used to explore the improving effect on the electrochemical performance of SnSe2. It is found that MXene etched by HF acid shows more obvious accordion-like structure with larger layer spacing, and its composite with SnSe2 demonstrates better lithium and potassium storage properties. When employed as potassium-ion batteries (PIBs) anode, MXene/SnSe2 electrode can deliver a reversible capacity of 222.8 mAh·g−1 till 300 cycles at the current density of 200 mA·g−1. As an anode for lithium-ion batteries (LIBs), MXene/SnSe2 could provide high reversible capacity (515.6 mAh·g−1 after 300 cycles at 200 mA·g−1) and rate capacity (1015.1 mAh·g−1 at 500 mA·g−1 and 496.2 mAh·g−1 at 5000 mA·g−1). Even at 2000 mA·g−1, the capacity of MXene/SnSe2 can be maintained at 322.6 mAh·g−1 after 500 cycles. Further analysis by ex-situ SEM finds that the MXene/SnSe2 electrode undergoes structural reconstruction at the high current density of 2000 mA·g−1. In the first few cycles, SnSe2 nanosheets are changed into a network structure and then in-situ pulverized into many small nanoparticles, all which immerged on MXene surface and between layers. Although MXene/SnSe2 electrode experiences structural transformation, it retains apparent layered structure. This provides a fast channel for electrons and ions migration, resulting in higher Li+ diffusion rate and diffusion-controlled storage capacity. It is believed that the work could be acted as a reference for design composite with MXene and used for anode as well as other materials.

Efficient Polytelluride Anchoring for Ultralong-Life Potassium Storage: Combined Physical Barrier and Chemisorption in Nanogrid-in-Nanofiber

HighlightsThe hierarchical nanogrid-in-nanofiber-structured dual-type carbon-confined CoTe2 nanodots (CoTe2@NC@NSPCNFs) were synthesized via facile templates and an electrospinning approach.Hierarchical nanogrid-in-nanofiber structure effectively suppresses the volume change of CoTe2 and the shuttle of potassium polytelluride (K-pTex) through robust physical restraint and strong chemisorption.CoTe2@NC@NSPCNFs hybrid achieves ultralong lifespan potassium-storage performance over 3500 cycles, and the deep mechanisms underlying the evolution, dissolution, and shuttle of K-pTex have been clearly revealed.

Strategies to boost the electrochemical performance of bismuth anodes for potassium-ion batteries.

Potassium-ion batteries (PIBs) are considered potential candidates for large-scale energy storage systems due to the abundant resources of potassium. Among various reported anode materials, bismuth anodes with the advantages of high theoretical specific capacity, low cost, and nontoxicity have attracted widespread attention. However, bismuth anodes experience significant volume changes during the charge/discharge process, leading to unsatisfactory cycling stability and rate performance. In this review, we focus on summarizing the research progress of bismuth anodes in PIBs. We discuss in detail the modification strategies for bismuth anodes in PIBs, including electrolyte optimization, morphology design, and hybridization with carbon materials. In addition, we attempt to propose possible future directions for the development of bismuth anodes in PIBs, aiming to expedite their practical application. It is believed that this review can assist researchers in more efficiently designing high-performance bismuth anode materials for PIBs.

Insight into Nanotransition Metal Disulfides as Anode for Potassium-Ion Batteries: Applications, Challenges, and Prospects

Potassium-ion batteries (PIBs) are highly attractive and are promising energy storage technology because of their cost-effectiveness, superior safety, environmental friendliness, as well as high standard K/K + redox potential, and abundance and low cost of potassium. Transition metal disulfides (TMDs) have a wide interlayer spacing that is attractive as a K + storage site in PIBs. Moreover, TMDs have high reversible capacity and are low cost. Nevertheless, they have not been extensively studied. The practical application of TMDs is impeded by their fast capacity fading and poor rate performance. More well-focused research should aim for the commercialization of TMDs in PIBs. This paper reviews (a) the main strategies to enhance the application of TMDs in PIBs; (b) the recent development of using TMDs such as MoS 2 , WS 2 , and SnS 2 as electrode materials for PIBs, including their structure, performance, and defects, as well as the methods to alleviate their defects; (c) the associated electrochemical processes; and (d) the critical issues, challenges, and prospects.

Interfacial tuning of the graphite anode for potassium ion intercalation in a wide temperature range

An electrolyte design strategy is proposed for graphite anode in potassium-ion batteries working in a wide temperature range.

Ginger-derived hierarchical porous carbon as an anode material for potassium-ion batteries and capacitors

Carbonaceous materials are ideal as an anode for potassium-ion batteries (KIBs) because of their low cost, tunable physiochemical properties, and excellent reversible intercalation of potassium-ions (K+).