Electrode Materials For Potassium-ion Batteries Research Articles

2D Se-Rich ZnSe/CoSe2@C Heterostructured Composite as Ultrastable Anodes for Alkaline-Ion Batteries.

2D transitional metal selenide heterostructures are promising electrode materials for potassium-ion batteries (PIBs) owing to the large surface area, high mechanical strength, and short diffusion pathways. However, the cycling performance remains a significant challenge, particularly concerning the electrochemical conversion reaction. Herein, 2D Se-rich ZnSe/CoSe2@C heterostructured composite is fabricated via a convenient hydrothermal approach followed by selenization process, and then applied as high-performance anodes for PIBs. For example, the capacity delivered by the heterostructured composite is mainly contributed to the synergistic effect of conversion and alloy/de-alloy processes aroused by K+, where K+ may highly insert or de-insert into Se-rich ZnSe/CoSe2@C. The obtained electrode delivers an outstanding reversible charge capacity of 214mA h g-1 at 1 A g-1 after 4000 cycles for PIBs, and achieves 262 mAh g-1 when coupled with a PTCDA cathode in the full cell. The electrochemical conversion mechanism of the optimized electrode during cycling is investigated through in situ XRD, Raman, and ex situ HRTEM. In addition, the heterostructured composite as anodes also displays excellent electrochemical performances for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). This work opens up a new window for investigating novel electrode materials with excellent capacity and long durability.

Flower-like CoSe2/N, P-doped carbon microspheres accommodated on carbon nanosheets for high-performance potassium-ion batteries

Transition metal selenides (TMSs) have emerged as promising electrode materials for potassium-ion batteries (PIBs), whereas the large volume expansion and sluggish reaction kinetics have seriously hindered the cycle life and rate performance. Herein, a hierarchical composite of flower-like CoSe2/N, P-doped carbon microspheres accommodated on carbon nanosheets (CoSe2-NPC@CNS) was rationally fabricated as the anode for PIBs through a one-pot hydrothermal and subsequent selenization method. The intimate hybridization of CoSe2/N, P-doped carbon microspheres can effectively alleviate the volume expansion of CoSe2 during charge-discharge cycles, and the ultrathin carbon nanosheets derived from fluid catalytic cracking (FCC) slurry serves as a highly conductive and buffered substrate. By robustly merging them together, the interconnected hierarchical nanoarchitecture with exposed active sites achieves promoted potassium storage capacity, electrochemical reaction kinetics, and structural stability. As a result, the PIBs with CoSe2-NPC@CNS anode deliver high reversible capacities of 320.8 mAh g−1 after 100 cycles at 0.1 A g−1 and 213.9 mAh g−1 after 850 cycles at 1.0 A g−1, excellent rate capability (188.8 mAh g−1 at 5 A g−1), and enhanced pseudo-capacitive contribution rate of 88.7 %. This work offers valuable insight into the rational design and development of hierarchical anode materials with high performance for PIBs and beyond.

Review on Layered Manganese-Based Metal Oxides Cathode Materials for Potassium-Ion Batteries: From Preparation to Modification.

Potassium-ion battery is rich in resources and cheap in price, in the era of lithium-ion battery commercialization, potassium-ion battery is the most likely to replace it. Based on the classification and summary of electrode materials for potassium-ion batteries, this paper focuses on the introduction of manganese-based oxide KxMnO2. The layered KxMnO2 has a large layer spacing and can be embedded with large size potassium-ions. This paper focuses on the preparation and doping of manganese-based cathode materials for potassium-ion batteries, summarizes the main challenges of KxMnO2-based cathode materials in the current stage of research and further looks into its future development direction.

Investigation on bare ZnO nanotubes and nanosheet as electrode materials for potassium-ion batteries: A DFT search

Within this work, the possibility of using (5,0), (6,0), (7,0), (8,0), and (9,0) zigzag ZnO nano-tubes and a ZnO nano-sheet (ZnONS) was investigated in potassium-ion batteries (KIBs) through the B3LYP-gCP-D3/6-31G* scheme. The cell voltage, ion diffusion coefficient, the maximum energy barrier for the migration of K+ and the adhesion energies of K+ and K of (5,0) nano-tube were 0.93 V, 5.31 × 10−8 cm2/s, –33.4 kcal/mol, respectively. The results showed that the impact of the dispersion term (D3) on the K and K+ adhesion energies was more than that of the gCP (basis set superposition error). A reduction in the curvature of the ZnONS dramatically weakened the interaction of the K atom, whereas it had a slight impact on the interaction of K+. Therefore, a decrease in the curvature of the ZnONS increased the cell voltage to 1.21 V. We can use ZnO nano-structures as a promising anode for KIBs.

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.

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.

Carbon Electrode Materials for Advanced Potassium-Ion Storage.

Tremendous progress has been made in the field of electrochemical energy storage devices that rely on potassium-ions as charge carriers due to their abundant resources and excellent ion transport properties. Nevertheless, future practical developments not only count on advanced electrode materials with superior electrochemical performance, but also on competitive costs of electrodes for scalable production. In the past few decades, advanced carbon materials have attracted great interest due to their low cost, high selectivity, and structural suitability and have been widely investigated as functional materials for potassium-ion storage. This article provides an up-to-date overview of this rapidly developing field, focusing on recent advanced and mechanistic understanding of carbon-based electrode materials for potassium-ion batteries. In addition, we also discuss recent achievements of dual-ion batteries and conversion-type K-X (X=O2 , CO2 , S, Se, I2 ) batteries towards potential practical applications as high-voltage and high-power devices, and summarize carbon-based materials as the host for K-metal protection and possible directions for the development of potassium energy-related devices as well. Based on this, we bridge the gaps between various carbon-based functional materials structure and the related potassium-ion storage performance, especially provide guidance on carbon material design principles for next-generation potassium-ion storage devices.

Review on recent advances of inorganic electrode materials for potassium-ion batteries

Review on recent advances of inorganic electrode materials for potassium-ion batteries

Recent Advances in 2D Heterostructures as Advanced Electrode Materials for Potassium‐Ion Batteries

Owing to the cost‐effectiveness, Earth abundance, and suitable redox potential, potassium‐ion batteries (PIBs) stand out as one of the best candidates for large‐scale energy storage systems. However, the large radius of K+ and the unsatisfied specific capacity are the main challenges for their commercial applications. To address these challenges, constructing heterostructures by selecting and integrating 2D materials as host and other materials as guest are proposed as an emerging strategy to obtain electrode materials with high capacity and long lifespan, thus improving the energy storage capability of PIBs. Recently, numerous studies are devoted to developing 2D‐based heterostructures as electrode materials for PIBs, and significant progress is achieved. However, there is a lack of a review article for systematically summarizing the recent advances and profoundly understanding the relationship between heterostructure electrodes and their performance. In this sense, it is essential to outline the promising advanced features, to summarize the electrochemical properties and performances, and to discuss future research focuses about 2D‐based heterostructures in PIBs.

Quinone-Based Ladder-Type Polymers as Promising Electrode Materials for Potassium-Ion Batteries

Quinone-Based Ladder-Type Polymers as Promising Electrode Materials for Potassium-Ion Batteries

Surface modification and in situ carbon intercalation of two-dimensional niobium carbide as promising electrode materials for potassium-ion batteries

Potassium ion batteries (KIBs) have a great potential in large scale energy storage because of their cost advantages and similar working mechanism to lithium ion batteries (LIBs). However, the larger ionic radius of K+ presents great challenges to find suitable electrode materials for K+ insertion/extraction. Herein, the surface-modified and in-situ carbon-intercalated Nb2CTx MXene is rationally designed and synthesized as electrode for KIBs. The as-prepared Nb2C/C has larger effective interlayer distance (i.e. gallery height), higher specific surface area and electrical conductivity, and lower concentration of surface functional groups. As a result, Nb2C/C exhibits a significantly increased coulombic efficiency (67.6% for Nb2C/C, 28.5% for Nb2CTx) and its specific capacity is two times higher than that of Nb2CTx at 0.02 A·g−1, three times at 0.1 A·g−1. The Nb2C/C delivers an initial specific capacity of 397.9 mAh·g−1 at 0.02 A·g−1 and 338.1 mAh·g−1 at 0.1 A·g−1, and maintains 80.0% after 100 cycles at 0.02 A·g−1 and 76.2% after 200 cycles at 0.1 A·g−1, respectively. Notably, Nb2C/C possesses outstanding cyclic stability and rate performance at various current densities, outperforming most of reported MXene-based anodes for KIBs. The excellent potassium storage performance of Nb2C/C can be ascribed to the abundant active sites exposed to electrolyte, rapid diffusion kinetics of K+ and few side reactions at the electrode/electrolyte interface. This work proposes an effective strategy for the MXene-based materials to maximize their potential applications in various fields such as batteries, supercapacitors and catalysts.

Unraveling the role of ion-solvent chemistry in stabilizing small-molecule organic cathode for potassium-ion batteries

Redox-active organic cathodes are promising high-capacity and low-cost electrode materials for potassium-ion batteries (KIBs), but usually suffer from poor cyclability due to the severe dissolution and notorious K dendrites. Herein, the effects of salt concentrations and solvents on the performance of potassium-organic batteries based on a typical phenothiazine derivative, methylene blue (MB), are explored, and the high-concentration potassium bis(fluorosulfonyl)amide-based ether electrolyte is versatile to achieve long lifespan. The high donor number and strong solvation ability of ether solvent endow MB cathode with high voltage plateaus and reversible capacity as compared to the carbonate counterpart. Moreover, the enhanced interactions of K+-ether and anion-participated ion-ether complexes in concentrated electrolyte not only decrease the amount of free solvent, but also contribute to forming highly ionic-conducting and thin anion-derived interphase layers, which effectively mitigate the shuttle effect and inhibit K dendrite growth. Consequently, MB cathode exhibits a high capacity of 139.5 mAh g−1 after 500 cycles at 0.1 A g−1, and long-term cycling stability for 4500 cycles. The good performance of full cells matched with graphite anode further demonstrates the feasibility of MB as KIB cathode. This work highlights the roles of ion-solvent chemistry in stabilizing small-molecule organic cathodes, which may bring new insights in the electrolyte design for wide organic electrode-based battery systems.

Fast and stable K-ion storage enabled by synergistic interlayer and pore-structure engineering

Carbon-based material has been regarded as one of the most promising electrode materials for potassium-ion batteries (PIBs). However, the battery performance based on reported porous carbon electrodes is still unsatisfactory, while the in-depth K-ion storage mechanism remains relatively ambiguous. Herein, we propose a facile “in situ self-template bubbling” method for synthesizing interlayer-tuned hierarchically porous carbon with different metallic ions, which delivers superior K-ion storage performance, especially the high reversible capacity (360.6 mAh·g−1@0.05 A·g−1), excellent rate capability (158.6 mAh·g−1@10.0 A·g−1) and ultralong high-rate cycling stability (82.8% capacity retention after 2,000 cycles at 5.0 A·g−1). Theoretical simulation reveals the correlations between interlayer distance and K-ion diffusion kinetics. Experimentally, deliberately designed consecutive cyclic voltammetry (CV) measurements, ex situ Raman tests, galvanostatic intermittent titration technique (GITT) method decipher the origin of the excellent rate performance by disentangling the synergistic effect of interlayer and pore-structure engineering. Considering the facile preparation strategy, superior electrochemical performance and insightful mechanism investigations, this work may deepen the fundamental understandings of carbon-based PIBs and related energy storage devices like sodium-ion batteries, aluminum-ion batteries, electrochemical capacitors, and dual-ion batteries.

Recent advances and perspective in metal coordination materials-based electrode materials for potassium-ion batteries

Recently, to ameliorate the forthcoming energy crisis, sustainable energy conversion and storage devices have been extensively investigated. Potassium-ion batteries (KIBs) have aroused widespread attention in these very active research applications due to their earth abundance and similar low redox potential compared to Li-ion batteries (LIBs). It is critical to develop electrode materials with large ion diffusion channels and robust structures for long cycling performance in KIBs. Metal coordination materials, including metal–organic frameworks, Prussian blue, and Prussian blue analogue, as well as their composites and derivatives, are known as promising materials for high-performance KIBs due to their open frameworks, large interstitial voids, functionality and tailorability. In this review, we give an overview of the recent advances on the application of metal coordination materials in KIBs. In addition, the methods to enhance their K-ion storage properties are summarized and discussed, such as morphology engineering, doping, as well as compositing with other materials. Ultimately, some prospects for future research of metal coordination materials for KIBs are also proposed.

Pyrrhotite Fe1\u2212xS microcubes as a new anode material in potassium-ion batteries

Potassium-ion batteries are an emerging energy storage technology that could be a promising alternative to lithium-ion batteries due to the abundance and low cost of potassium. Research on potassium-ion batteries has received considerable attention in recent years. With the progress that has been made, it is important yet challenging to discover electrode materials for potassium-ion batteries. Here, we report pyrrhotite Fe1−xS microcubes as a new anode material for this exciting energy storage technology. The anode delivers a reversible capacity of 418 mAh g−1 with an initial coulombic efficiency of ~70% at 50 mA g−1 and a great rate capability of 123 mAh g−1 at 6 A g−1 as well as good cyclability. Our analysis shows the structural stability of the anode after cycling and reveals surface-dominated K storage at high rates. These merits contribute to the obtained electrochemical performance. Our work may lead to a new class of anode materials based on sulfide chemistry for potassium storage and shed light on the development of new electrochemically active materials for ion storage in a wider range of energy applications.

Porous-Carbon Aerogels with Tailored Sub-Nanopores for High Cycling Stability and Rate Capability Potassium-Ion Battery Anodes.

Developing advanced electrode materials for potassium-ion batteries (PIBs) is an emerging research area in recent years; so far, several strategies such as heteroatom doping into carbon, increasing interlayer spacing, or creating amorphous region in graphite have been investigated. Here, we studied the effect of sub-nanopores in a porous-carbon aerogel with a pore size distribution centered at around 0.8 nm and achieved outstanding PIB performance including long cycling stability (particularly at small current densities for prolonged charge/discharge period) and high rate capability with enhanced retentions. Mechanism studies reveal very high contribution from surface capacitive potassium (K)-ion storage (more than 90%) to the total capacity, and theoretical calculations show that 0.8 nm sub-nanopores lead to substantially low barrier for K-ion transport and storage, with ultrasmall diffusion energy and negligible lattice change. Sub-nanopore engineering, as demonstrated here, may be adopted to develop highly efficient and stable porous-carbon-based structures for applications in advanced energy storage systems and electrochemical catalysis.

Recent Research Progress of Anode Materials for Potassium‐ion Batteries

The next‐generation smart grid for the storage and delivery of renewable energy urgently needs to develop a low‐cost and rechargeable energy storage technology beyond lithium‐ion batteries (LIBs). Owing to the abundance of potassium (K) resources and the similar electrochemical performance to that of LIBs, potassium‐ion batteries (PIBs) have been attracted considerable interest in recent years, and significant progress has been achieved concerning the discovery of high‐performance electrode materials for PIBs. This review especially summarizes the latest research progress regarding anode materials for PIBs, including carbon materials, organic materials, alloys, metal‐based compounds, and other new types of compounds. The reversible K‐ion storage principle and the electrochemical performance (i.e., capacity, potential, rate capability, and cyclability) of these developed anode materials are summarized. Furthermore, the challenges and the corresponding effective strategies to enhance the battery performance of the anode materials are highlighted. Finally, prospects of the future development of high‐performance anode materials for PIBs are discussed.

Dual Interphase Layers In Situ Formed on a Manganese-Based Oxide Cathode Enable Stable Potassium Storage

Summary Mn-based oxides have attracted extensive attention as electrode materials. However, the irreversible phase transition and Mn2+ dissolution result in their structure instability and performance decay. Here, we report dual interphase layers in situ formed on P2-K0.67MnO2 (P2-KMO) in 6.0 M of potassium bis(fluorosulfonyl)amide in diglyme (KFSI/G2) during charging. It is composed of a solid-electrolyte interphase (SEI) and K-poor spinel interlayer on P2-KMO, which are derived from the simultaneous decomposition of 6.0 M KFSI/G2 and disproportionation of surface Mn3+. They cooperatively enable the reversible phase transition of P2↔P″2 in the bulk P2-KMO and mitigate Mn loss. This leads to a high capacity retention of 90.5% and a Coulombic efficiency of 100% after 300 cycles. The investigation highlights the significance of interphase chemistry of electrode materials for potassium-ion batteries and beyond.

Partial replacement of K by Rb to improve electrochemical performance of K3V2(PO4)3 cathode material for potassium-ion batteries

Rb-doped K3-xRbxV2(PO4)3/C (x = 0, 0.03, 0.05 and 0.07) composites for high-voltage cathode have been synthesized via a facile sol-gel process. The as-prepared materials have been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical tests. SEM and TEM show that the Rb-doped K3V2(PO4)3/C composites exhibit similar morphology and particle sizes to the undoped one. The electrochemical tests demonstrate that the Rb-doped composites with varied Rb contents deliver better electrochemical performance than the pristine K3V2(PO4)3/C, where K2.95Rb0.05V2(PO4)3/C performs the best. In the voltage range of 2.5–4.6 V (vs. K+/K) at 20 mA g−1, K3V2(PO4)3/C and K2.95Rb0.05V2(PO4)3/C display initial discharge capacities of 41.1 and 55.7 mAh g−1, respectively. The corresponding discharge capacities decrease to 32.1 and 52.6 mAh g−1 after 50 cycles, respectively. At a current density as high as 200 mA g−1, K2.95Rb0.05V2(PO4)3/C still presents higher initial discharge capacity of 34.5 mAh g−1 with a capacity retention of 95.4% after 100 cycles, while K3V2(PO4)3/C only shows the initial discharge of 21.1 mAh g−1 with the capacity retention of 85.7%. The improvement in electrochemical performance of Rb-doped K3V2(PO4)3/C is attributed to the doping of Rb into K sites of K3V2(PO4)3 and this doping can increase the K+ diffusion coefficients in electroactive particles. The results imply that replacement of K+ by larger cations is also helpful to improve the electrochemical performance of other K-containing electrode materials for potassium-ion batteries.

Snapshot on Negative Electrode Materials for Potassium-Ion Batteries

Potassium-based batteries have recently emerged as a promising alternative to lithium-ion batteries. The very low potential of the K + /K redox couple together with the high mobility of K + in electrolytes resulting from its weak Lewis acidity should provide high energy density systems operating with fast kinetics. However, potassium metal cannot be implemented in commercial batteries due to its high reactivity. As safety is one of the major concerns when developing new types of batteries, it is therefore crucial to look for materials alternative to potassium metal that electrochemically insert K + at low potential. Here, the different types of negative electrode materials highlighted in many recent reports will be presented in detail. As a cornerstone of viable potassium-ion batteries, the choice of the electrolyte will be addressed as it directly impacts the cycling performance. Lastly, guidelines to a rational design of sustainable and efficient negative electrode materials will be proposed as open perspectives.