Anode For Potassium-ion Batteries Research Articles

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+).

Highly crystalline graphite nanofibers as an anode for high-performance potassium-ion batteries

Graphite nanofibres with high crystallinity and low defect levels for potassium-ion batteries with high initial Coulombic efficiency and long cycling stability are reported in this study.

SAXS unveils porous anodes for potassium-ion batteries: dynamic evolution of pore structures in Fe@Fe2O3/PCNFs composite nanofibers.

The porous structure of composite nanofibers plays a key role in improving their electrochemical performance. However, the dynamic evolution of pore structures and their action during ion intercalation/extraction processes for negative electrodes are not clear. Herein, porous carbon composite nanofibers (Fe@Fe2O3/PCNFs) were prepared as negative electrode materials for potassium-ion batteries. Electrochemical test findings revealed that the composites had good electrochemical characteristics, and the porous structure endowed composite electrodes with pseudo-capacitive behaviors. After 1500 discharge/charge cycles at a current density of 1000 mA g-1, the specific capacity of the potassium-ion batteries was 144.8 mAh g-1. We innovatively used synchrotron small-angle X-ray scattering (SAXS) technique to systematically investigate the kinetic process of potassium formation in composites and showed that the kinetic process of potassium reaction in composites can be divided into four stages, and the pores with smaller average diameter distribution are more sensitive to changes in the reaction process. This work paves a new way to study the deposition kinetics of potassium in porous materials, which facilitates the design of porous structures and realizes the development of alkali metal ion-anode materials with high energies.

A bimetallic sulfide FeCoS4@rGO hybrid as a high-performance anode for potassium-ion batteries.

We synthesized a low metal-to-sulfur atomic ratio (0.5) FeCoS4, exhibiting high reversible specific capacity. Reduced graphene oxide was covered on the surface to improve the cycling stability and rate performance further. Density functional theory calculations show that composite materials can effectively increase the adsorption energy and enhance the diffusion kinetics.

Advances in bismuth-based anodes for potassium-ion batteries

Bi-based materials with low cost, high capacity and suitable operating voltage are promising candidates for potassium-ion battery anodes. Rational optimization strategies are expected to bring them from laboratory to commercial applications.

Anisotropic lens-shaped mesoporous carbon from interfacially perpendicular self-assembly for potassium-ion batteries.

Anisotropic lens-shaped nitrogen-doped carbon (Lens-NMC) with unidirectionally aligned mesopores was achieved via perpendicular block copolymer self-assembly at the polymer interface. Lens-NMC is applied as a potassium-ion battery anode material as a next-generation battery system.

Deciphering Unexplored Reversible Potassium Storage and Small Volume Change in a CaV4O9 Anode with In Situ Transmission Electron Microscopy

AbstractVanadium‐based compounds are explored as promising electrode materials in lithium/sodium‐ion batteries exhibiting superior energy storage properties. However, similar attempts are rarely reported for potassium‐ion batteries (PIBs), in which the fundamental reaction mechanisms remain inexplicit. Herein, porous CaV4O9 nanobelts (NBs) are selected as a PIB anode to systematically investigate potassium storage mechanisms through in situ transmission electron microscopy. In situ measurements track overall electrochemical potassiation reactions of CaV4O9 and identify a polyphase state of V4O7, CaO, and K2O phases after potassiation. Unexpectedly, the potassiated products can be partially converted back to the original CaV4O9 phase with residual VO2 and CaO phases, which is different from the irreversible phase transformations in lithium/sodium storages of CaV4O9. Impressively, the cavities in NBs alternately disappear and appear with (de)potassiation, avoiding the drastic volume change and structural degradation of anodes. The reversible potassium storage and stable cycling are evaluated by electrochemical measurements and in situ X‐ray diffraction analysis. This work provides a paradigm by revisiting the existing anode materials in lithium/sodium‐ion batteries to seek out viable anodes for next‐generation PIBs.

Modulating Co[sbnd]Co bonds average length in Co0.85Se1−xSx to enhance conversion reaction for potassium storage

While alloying transition metal chalcogenides (TMCs) with other chalcogen elements can effectively improve their conductivity and electrochemical properties, the optimal alloying content is still uncertain. In this study, we study the influence of dopant concentration on the chemical bonds in TMC and reveal the associated stepwise conversion reaction mechanism for potassium ion storage. According to density function theory calculations, appropriate S-doping in Co0.85Se (Co0.85Se1−xSx) can reduce the average length of CoCo bonds because of the electronegativity variation, which is thermodynamically favourable to the phase transition reactions. The optimal Se/S ratio (x = 0.12) for the conductivity has been obtained from experimental results. When assembled as an anode in potassium-ion batteries (PIBs), the sample with optimized Se/S ratio exhibits extraordinary electrochemical performance. The rate performance (229.2 mA h g−1 at 10 A g−1) is superior to the state-of-the-art results. When assembled with Prussian blue (PB) as a cathode, the pouch cell exhibits excellent performance, demonstrating its great potential for applications. Moreover, the stepwise K+ storage mechanism caused by the coexistence of S and Se is revealed by in-situ X-ray diffraction and ex-situ transmission electron microscopy techniques. Hence, this work not only provides an effective strategy to enhance the electrochemical performance of transition metal chalcogenides but also reveals the underlying mechanism for the construction of advanced electrode materials.

A universal method for N/B codoped carbon bubbles for enhanced potassium ion storage

Carbon materials are widely regarded as highly promising anode materials for potassium ion batteries due to their features of tunable structure, affordable price, excellent conductivity, and favorable chemical stability. However, due to the sluggish potassium storage kinetics and relatively severe volumetric effect brought about by the large radius of potassium ions, carbon materials often suffer from unsatisfactory reversible capacity and weak rate performance. In this work, we propose to prepare a distinctive dual-atom doped carbon bubble material by a simple self-templating method. This unique structural design results in a high specific surface area, large layer spacing, abundant pore structure and enriched active sites. Owing to these merits, the N, B-doped carbon exhibits a high reversible capacity (534.0 mA h g−1 at 0.1 A g−1 after 200 cycles), long-term cycling stability and excellent rate capacity when used as the anode for potassium-ion batteries. The results of electrochemical kinetic studies indicate that capacitance control effects play a dominant role in the total energy storage mechanism. Furthermore, this preparation method has good generalizability and is expected to have applications in other batteries, supercapacitors or catalysis.

Thermal Induced Conversion of CoFe Prussian Blue Analogs Nanocubes Wrapped by Doped Carbon Network Exhibiting Fast and Stable Potassium Ion Storage as Anode.

Prussian blue analogs (PBAs) show great promise as anode materials for potassium-ion batteries (PIBs) due to their high specific capacity. However, PBAs still suffer from the drawbacks of low electronic conductivity and poor structural stability, leading to inadequate rate and cyclic performance. To address these limitations, CoFe PBA nanocubes wrapped with N/S doped carbon network (CoFe PBA@NSC) as anode for PIBs is designed by using thermal-induced in situ conversion strategy. As expected, the structural advantages of nanosized PBA cubes, such as abundant interfaces and large surface area, enable the CoFe PBA@NSC electrode to demonstrate superior rate properties (557 and 131mAhg-1 at 0.05 and 10Ag-1) and low capacity degradation (0.093% per cycle over 1000 cycles at 0.5Ag-1). Furthermore, several ex situ characterizations revealed the K-ion storage mechanism. Fe+ and Co0 are generated during potassicization, followed by a completely reversible chemical state of iron while some cobalt monomers remained during depotassication. Additionally, the as-built potassium-ion hybrid capacitor based on CoFe PBA@NSC anode exhibits a high energy density of 118Whkg-1. This work presents an alternative but promising synthesis route for Prussian blue analogs, which is significant for the advancement of PIBs and other related energy storage devices.