Anode For Potassium-ion Batteries Research Articles

Nanowire sulfide/carbon composite with high electrochemical performance in potassium-ion batteries

Transition metal chalcogenides (TMCs) have demonstrated great potential in energy storage devices due to their versatile structures and composite functionalities. However, the application of TMCs in potassium-ion batteries (PIBs) suffers from the issues of large volume expansion, polysulfide dissolution, and sluggish kinetics. To overcome these challenges, this work develops nano-flower-like MnS-Co3S4 confined in poly-pyrrole (PPY) carbon nanotube (denoted as MS-CS-PPY) as an excellent anode in PIBs. The nitrogen-doped PPY framework facilitates the interface electron transfer, confines active materials MS-CS effectively, and mitigates the volume change, thus resulting in boosted reaction kinetics and exceptional cycling stability. TMCs induce the surface capacitance and enable the chemical anchoring of the charge/discharge products during the potassium/de-potassium process. Moreover, this work reveals the potassium/de-potassium reaction mechanism, redox kinetics, and solid electrolyte interphase formation of MS-CS-PPY in different electrolytes through theoretical calculations and experimental studies. The solvation ability of electrolytes plays a vital role in manipulating the redox kinetics of the MS-CS-PPY anode material. This study offers feasible strategies for electrode design and electrolyte selection for developing TMCs negative electrodes in future PIBs.

Mixed-biomass engineering achieves multi-doped highly-disordered hierarchical flower-like hard carbon for advanced potassium-ion battery

Potassium-ion batteries (PIBs) have emerged as a significant technology for large-scale energy storage. With merits of high abundance, sustainability, and low cost, hard carbons are employed as promising anodes for PIBs, yet distorted carbon lattice induces sluggish conductivity and structural degradation, posing key challenges of low power performance and inferior life span. Here, we proposed a mixed-biomass strategy to design a multi-doped flower-like carbon micro-sphere with major doping of N and trace doping of P and S (NPS-FCM) for advanced PIBs operation. The mixed-biomass engineering achieved inherently rich heteroatoms’ doping and highly disordered hierarchical configuration simultaneously. The NPS-FCM material with expanded lattice spacing, larger specific area, and abundant edge defects and pores, offers robust rate property, and impressive cycle life (1000 cycles with 0.147 ‰ capacity decay per cycle). The potassium-ion full cell (NPS-FCM//PTCDA) was also implemented to show a high median-voltage of 1.78 V and steady cycling. Density functional theory calculation convinced the upgraded electronic conductivity and lowered adsorption energy for potassium storage. This work highlights the importance of mixed-biomass’ cooperation to provide pivotal guidance for sustainable and advanced electrodes for next-generation energy storage.

Robust Micro-Sized and Defect-Rich Carbon-Carbon Composites as Advanced Anodes for Potassium-Ion Batteries.

Pitch-derived carbon (PC) anode features the merits of low-cost, rich edge-defect sites, and tunable crystallization degree for potassium ion batteries (PIBs). However, gaining the PC anode with both rich edge-defect sites and robust structure remains challenging. Herein, micro-sized and robust PC/expanded-graphite (EG) composites (EGC) with rich edge-defect sites are massively synthesized via melting impregnation and confined pyrolysis. The PC is in situ encapsulated in micro-sized EG skeleton with robust chemical bonds between PC and EG after thermal treatment, endowing the structural stability as micro-sized carbon-carbon composites. The confinement effect originating from EG skeleton could suppress the crystallization degree of the PC and contribute rich edge-defect sites in EGC composites. Additionally, the EG skeleton inside EGC could form continuous electronic conduction nets and establish low-tortuosity carbonaceous electrodes, facilitating rapid electron/ion migration. While applied in PIBs, the EGC anode delivers a reversible capacity that up to 338.5mAhg-1 at 0.1Ag-1 , superior rate performance of 127.5mAhg-1 at 5.0Ag-1 , and long-term stability with 204.8mAhg-1 retain after 700 cycles at 1.0Ag-1 . This novel strategy highlights an interesting category of heterogeneous carbon-carbon composite materials to keep pace with the demand for the future PIBs industry.

Fast and Long‐Lasting Potassium‐Ion Storage Enabled by Rationally Engineering Strain‐Relaxation Bi/Bi2O3 Nanodots Embedded in Carbon Sheets

AbstractBismuth (Bi)‐based materials merit high theoretical volumetric specific capacity (3800 mAh mL⁻1) but suffer from huge volume variations and sluggish reaction kinetics during cycling. Herein, the optimal framework of Bi/Bi2O3 nanodots enriched in suitable outer amorphous carbon sheets (Bi/Bi2O3 NDs@CSs) is first proposed to alleviate volume variations and accelerate stable charge transport to boost K+ storage performance. The introduction of proper Bi2O3 not only provides an efficient K+ adsorption path, but also effectively buffers volume changes via conversion reaction. Accordingly, the as‐prepared anode exhibits a remarkable rate capability (149.3 mAh g−1 at 60 A g−1, 42% capacity retention with a 120‐fold current‐density increase) and extraordinary durability (1800 cycles at 5.0 A g−1, 95% capacity retention), among the best rate and cycling performance to date in potassium ion batteries (PIBs) anodes. Theoretical calculations reveal the feasible structures of Bi/Bi2O3 NDs@CSs with double protection of carbon sheets and Bi2O3 are conducive to enhance charge transfer and efficiency of electrochemical reaction. Substantial in situ/ex situ characterizations and finite element simulation further unveil high reversibility and robust mechanical behavior of Bi/Bi2O3 NDs@CSs, favorable for the reinforcement of structural stability. This study provides new insights into developing high‐performance and durable Bi‐based anodes for PIBs.

Recent Advances and Challenges in Ti-Based Oxide Anodes for Superior Potassium Storage.

Developing high-performance anodes is one of the most effective ways to improve the energy storage performances of potassium-ion batteries (PIBs). Among them, Ti-based oxides, including TiO2, K2Ti6O13, K2Ti4O9, K2Ti8O17, Li4Ti5O12, etc., as the intrinsic structural advantages, are of great interest for applications in PIBs. Despite numerous merits of Ti-based oxide anodes, such as fantastic chemical and thermal stability, a rich reserve of raw materials, non-toxic and environmentally friendly properties, etc., their poor electrical conductivity limits the energy storage applications in PIBs, which is the key challenge for these anodes. Although various modification projects are effectively used to improve their energy storage performances, there are still some related issues and problems that need to be addressed and solved. This review provides a comprehensive summary on the latest research progress of Ti-based oxide anodes for the application in PIBs. Besides the major impactful work and various performance improvement strategies, such as structural regulation, carbon modification, element doping, etc., some promising research directions, including effects of electrolytes and binders, MXene-derived TiO2-based anodes and application as a modifier, are outlined in this review. In addition, noteworthy research perspectives and future development challenges for Ti-based oxide anodes in PIBs are also proposed.

Ultrastable Graphite-Potassium Anode through Binder Chemistry.

Graphite with abundant reserves has attracted enormous research interest as an anode of potassium-ion batteries (PIBs) owing to its high plateau capacity of 279 mAh g-1 at ≈0.2V in conventional carbonate electrolytes. Unfortunately, it suffers from fast capacity decay during K+ storage. Herein, an ultrastable graphite-potassium anode is developed through binder chemistry. Polyvinyl alcohol (PVA) is utilized as a water-soluble binder to generate a uniform and robust KF-rich SEI film on the graphite surface, which can not only inhibit the electrolyte decomposition, but also withstand large volume expansion during K+ -insertion. Compared to the PVDF as binder, PVA-based graphite anode can operate for over 2000 cycles (running time of 406 days at C/3) with 97% capacity retention in KPF6 -based electrolytes. The initial Coulombic efficiency (ICE) of graphite anode is as high as 81.6% using PVA as the binder, higher than that of PVDF (40.1%). Benefiting from the strong adhesion ability of PVA, a graphite||fluorophosphate K-ion full battery is further built through 3D printing, which achieves a record-high areal energy of 8.9 mWh cm-2 at a total mass loading of 38mg cm-2 . These results demonstrate the important role of binder in developing high-performance PIBs.

Construction of mesoporous N-doped carbon-coated MXene-MoS2 heterostructured microspheres via a spray-drying method as a high capacity and long cycle-life anode for potassium-ion batteries

Heterostructured materials with 2D architecture capitalizing on the unique benefits of each component and the emergent properties from their synergy have ignited considerable interest in the field of rechargeable batteries. Nevertheless, inhibiting the restacking issue inherent to 2D materials and optimizing the structural design to enhance the electrochemical reactions continue to pose substantial challenges. In this study, we successfully fabricated porous 3D N-doped carbon microspheres consisting of MXene and molybdenum disulfide (MX/MoS2 @NC) for use as an electrode material in potassium-ion batteries via a facile spray-drying method. The MX/MoS2 @NC electrode showcased excellent electrochemical properties as an anode, delivering stable cycling performance and minimal capacity decay (350 mA h g−1 at 0.5 A g−1 after 400 cycles). It also exhibits improved rate capability and enhanced ion transport kinetics (219 mA h g−1 at 2.0 A g−1). The high performance of this composite can be traced back to its 3D microspherical structure facilitating efficient ion transport, the synergy between MXene and N-doped carbon enhancing its structural robustness and electrical conductivity, and the 2D MXene nanosheets preventing MoS2 restacking. This investigation underscores the MX/MoS2 @NC composite as a promising candidate for potassium-ion battery applications.

Enhancing potassium ions adsorption on mesoporous carbon spheres with abundant internal surface via engineering sulfur doping sites towards superior rate capability

Mesoporous carbon spheres (MCSs) show great potential for using as high-performance anodes in potassium-ion batteries (PIBs). Design and synthesis of MCSs with suitable multiscale structures and heteroatom doping or co-doping in MCSs are successfully employed to optimize the ion and electron transportation, however, it is still a challenge to explore MCS-based anodes with satisfactory potassium storage performance. In this work, we report novel S-doped MCS samples with abundant internal surfaces for potassium storage. The S doping sites are controlled during the synthesis, and the effect of different doping sites on the potassium storage is systematically studied. It is found that S doping between the carbon layers enlarges interlayer spacing and facilitates potassium ion adsorption. Consequently, the optimized sample shows an excellent rate capability of 144 mAh/g at 5.0 A/g, and a high reversible specific capacity of 325 mAh/g after 100 cycles at 0.1 A/g with a capacity retention of 91.2%. The important role of element doping sites on ion adsorption and ion storage performance is confirmed by theoretical investigations. Controlling the doping sites in MCSs provides a new approach to designing high-performance electrodes for energy storage and conversion applications.

Bamboo-like tubular nitrogen-doped carbon derived from g-C3N4 as an ultra-high performance anode of potassium-ion battery

Carbon materials are still the most widely studied anode materials for potassium ion batteries (PIBs) attributed to their advantages of wide source, controllability, and environmental friendliness. In this paper, a bamboo-like tubular nitrogen-doped carbon material (CNC) was prepared by using g-C3N4 as the precursor and transition metal salt as the catalyst and template. CNC has the advantages of a bamboo-like tubular structure, rich nitrogen content, and large layer spacing. As anode of PIBs, CNC can deliver an impressive initial reversible capacity of 488.6 mAh/g at 0.1 A/g. At a high current density of 1 A/g, CNC still retains a reversible capacity of 291 mAh/g after 1000 cycles. The excellent performance of CNC anode can be due to the porous bamboo-like tubular structure that promotes K ions diffusion and the rich nitrogen content that provides abundant active sites for K ions.

Short-Range Graphitic Nanodomains in Hypocrystalline Carbon Nanotubes Realize Fast Potassium Ion Migration and Multidirection Stress Release.

Defect-rich carbon materials are considered as one of the most promising anodes for potassium-ion batteries due to their enormous adsorption sites of K+ , while the realization of both rate capability and cycling stability is still greatly limited by unstable electrochemical kinetics and inevitable structure degradation. Herein, an Fe3+ -induced hydrothermal-pyrolysis strategy is reported to construct well-tailored hybrid carbon nanotubes network architecture (PP-CNT), in which the short-range graphitic nanodomains are in-situ localized in the pea pod shape hypocrystalline carbon. The N,O codoped hypocrystalline carbon region contributes to abundant defect sites for potassium ion storage, ensuring high reversible capacity. Meanwhile, the short-range graphitic nanodomains with expanded interlayer spacing facilitate stable K+ migration and fast electron transfer. Furthermore, the finite element analysis confirms the volume expansion caused by K+ intercalation can be availably buffered due to the multidirection stress release effect of the unique porous pea pod shape, endowing carbon nanotubes with superior structural integrity. Consequently, the PP-CNT anode exhibits superior potassium-storage performance, including high reversible capacity, exceptional rate capability, and ultralong cycling stability. This work opens a new avenue for the fabrication of advanced carbon materials for achieving durable and fast potassium storage.

Antimony/Polypyrrole/CNTs composites with three-dimensional structure as highly stable anodes for potassium ion battery

Antimony (Sb)-based materials are attractive as anodes in potassium ion batteries (PIBs). However, poor cycling and volume expansion of the Sb-based anodes hinder their development in PIBs. In this work, we prepared a novel three-dimensional Sb nanoparticle/polypyrrole/carbon nanotube (Sb/PPy/CNT) hybrid anode material. The obtained Sb/PPy/CNT maintained a discharge capacity of 555.1 mAh g−1 after 200 cycles at a current density of 100 mA g−1, and 347.5 mAh g−1 after 600 cycles at a high current density of 1000 mA g−1, showing outstanding potassium storage capacity and cycling performance. This excellent performance was attributed to the array of electron transfer networks formed in the hydrogel network, as well as inhibition of the volume expansion exhibited by potassium ions during embedding/detachment of the CNTs and Sb nanoparticles arising from encapsulation by PPy films. This study provides a prerequisite for expanding the use of high-performance anode materials for PIBs.

Advancements and Prospects of Graphite Anode for Potassium-Ion Batteries.

Potassium-ion batteries (KIBs) have recently attracted considerable attention owing to their resource abundance, low cost and environmental friendliness. Graphite as a mature commercial anode material for lithium-ion batteries, has been proved as a promising anode candidate for KIBs by reversible forming potassium-graphite intercalation compounds. However, large volume expansion and sluggish K+ kinetics caused by the incompatibility between large radius of K+ and the small interlayer spacing of graphite, result in the poor cycle stability and rate performances, hindering its practical application. Extensive research efforts have focused on improving the potassium storage performance of graphite anodes. This review provides an overview of recent advances in addressing these challenges and optimizing the electrochemical performance of graphite anodes for KIBs. Various strategies to improve the electrochemical performance of graphite and graphitic carbon anodes, such as microcrystalline regulation, heteroatom doping, morphological adjustment, and coating modification, are discussed, while the critical issues and challenges associated with graphite anodes and the prospects for their advancement in KIBs are highlighted. The review offers valuable guidelines for rational structural design and promotes the commercial development of high-performance graphite anode materials for KIBs.

Utilization of PET derived hard carbon as a battery-type, higher plateau capacity anode for sodium-ion and potassium-ion batteries

Trash to Treasure is a less energy-intensive approach for upcycling plastic waste into value-added products to generate sustainable, cost-effective, eco-friendly materials. The carbonization of polyethylene terephthalate (PET) via a single-step process into hard carbon (HC) delivers a high-performing anode material for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). Direct pyrolysis of PET waste increases the interlayer spacing with partially closed slit-shaped micro and mesopores that significantly improves the lower potential plateau-based capacity to 68% of the total capacity, validating a battery-type anode material. The HC carbonized at 1000℃ delivers a reversible capacity of 337 mAh/g with capacity retention of 88% after 100 cycles at 30 mAh/g. The HC exhibits 80% capacity retention even after 1000 cycles at a 1C rate and is promising for fast cycling-high power density applications. In PIBs, the HC carbonized at 800℃ performs the best and shows a reversible capacity of 305 mAh/g, with a battery-type low voltage plateau contribution of 32%. The charge storage mechanism in SIBS and PIBs follows a three-stage storage mechanism, i.e., adsorption, intercalation, and pore-filling.

Tungsten chalcogenides as anodes for potassium-ion batteries

Tungsten chalcogenides as anodes for potassium-ion batteries

Ultrafine red phosphorus confined in reasonably designed pitch-based carbon matrix built of well-interconnected carbon nanosheets for high-performance lithium and potassium storage

Red phosphorus has been well-recognized as promising anode materials for lithium-ion batteries (LIBs) and potassium-ion batteries (PIBs) due to its extremely high theoretical capacity and low cost. However, the huge volume change and poor electric conductivity severely limit its further practical application. Herein, the nanoscale ultrafine red phosphorus has been successfully confined in a three-dimensional pitch-based porous carbon skeleton composed of well-interconnected carbon nanosheets through the vaporization-condensation method. Except for the traditional requirement of high electric conductivity and stable mechanical stability, the micropores and small mesopores in the porous carbon matrix centered at 1 to 3 nm and the abundant amount of oxygen-containing functional groups are also beneficial for the high loading and dispersion of red phosphorus. As anode for LIBs, the composite exhibits high reversible discharge capacities of 968 mAh g−1, excellent rate capabilities of 593 mAh g−1 at 2 A g−1, and long cycle performance of 557 mAh g−1 at 2 A g−1. More impressively, as the anode for PIBs, the composite presents a high reversible capacity of 661 mAh g−1 and a stable capacity of 312 mAh g−1 at 0.5 A g−1 for 500 cycles with a capacity retention up to 84.3%. This work not only sheds light on the structure design of carbon hosts with specific pore structure but also open an avenue for high value-added utilization of coal tar pitch.

Low-Cost Pitch Derived Lamellar N-Doped Carbon as a High-Performance Potassium-Ion Battery Anode

Low-Cost Pitch Derived Lamellar N-Doped Carbon as a High-Performance Potassium-Ion Battery Anode

Porous nitrogen-doped FeP/C nanofibers as promising anode for potassium-ion batteries

Porous nitrogen-doped FeP/C nanofibers as promising anode for potassium-ion batteries

The g-C3N4-derived nanoarchitectonics of nitrogen-doped carbon material as a high-rate performance anode for potassium ion batteries

Due to the advantages of abundant precursors, simple preparation, and environmental friendliness, nitrogen-doped carbon is considered one of the most potential anodes for potassium ion batteries (PIBs). Here, nitrogen-doped carbon materials (NC-2) were prepared by using secondary exfoliated g-C3N4 as a precursor, combined with sucrose, and subjected to hydrothermal and high-temperature pyrolysis. NC-2 is characterized by high nitrogen content, porous layered structure, and large interlayer spacing. NC-2 used as anode of PIBs shows a high reversible capacity of 261.07 mAh g−1 at 0.1 A g−1 and an impressive rate performance of 153.36 mAh g−1 at 2 A g−1. The impressive performance of NC-2 can be originated from the porous layered structure and enlarged interlayer spacing promotes the intercalation/deintercalation and the diffusion of K ions, and the defective carbon structure formed after nitrogen doping can supply abundant active sites for K ions. The results show that NC-2 has great potential in the field of PIBs anode.

Amorphous carbon with N-S bond active center for enhanced capacitive contribution of potassium-ion batteries

Carbon materials have great potential in achieving excellent potassium-ion batteries (PIBs), while the low theoretical capacity of carbon materials limits the application of potassium ion batteries. Here, we reported an amorphous porous carbon with rich N-S bonds (N-S/C) by simple self-assembly possess and pyrolysis possess. The prepared N-S/C material possesses plentiful N-S bonds, which can act as active center to enhance the electrochemical capacity and accelerate transport dynamics. In addition, abundant porous structure can increase the contact area between electrode materials and electrolyte to shortens the diffusion path of ion transport, thereby improving the rate performance. As PIBs anodes, the N-S/C material exhibits a markedly enhanced reversible capacity of 389 mAh g−1 at 50 mA g−1, excellent cycling stability (188.8 mAh g−1 at 500 mA g−1 after 1000 cycles) and rate performance (105 mAh g−1 at 2 A g−1). Importantly, the in-situ Raman unravels a reversible mechanism that intercalation/deintercalation of K+ into/from the N-S/C, and the electrochemical analysis shows the N-S bond can improve the capacitive activity and enable fast kinetics toward superior K+-storage. These results demonstrate a promising carbonaceous anode material for PIBs and may provide guidance for designing of electrode materials of PIBs.

Improved electrochemical performance of soft carbon derived from coal liquefaction residue coated with expanded graphite for Lithium/Potassium batteries

This study investigated the use of asphaltene from coal liquefaction residue (CLRA) as a precursor for creating carbon nanosheets, which were then used to create a unique sandwich structure of soft carbon (SC) coated with expanded graphite (EG) composite (SC@EG) anodes for both lithium-ion and potassium-ion batteries. The SC@EG was formed through a covalent bond between EG and SC, resulting in a porous structure with favorable porosity and copious defects that expedited the migration of both Li+ and K+ ions. The SC@EG showed good electrochemical properties including high reversible capacity (510 mAh/g at 0.5 A/g in LIBs and 268 mAh/g at 0.1 A/g in KIBs), good rate performance (172 mAh/g at 4 A/g in LIBs and 154 mAh/g at 1 A/g in KIBs) and cyclic stability, attributed to the exceptional electronic conductivity and profound porosity of the structure.