Anode For Potassium-ion Batteries Research Articles

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.

Ultrasound-assisted successive recovery of chemical activation agent and synthesis of high sulfur petroleum coke-based carbon anode with progressively improving performance K-ion storage

The effectiveness of continuous synthesis of petroleum coke-based potassium ion battery anodes by chemical activation agent cycle was systematically studied. The potassium ions storage performance in the synthesized carbon anode was measured. High‑sulfur petroleum coke, as a natural sulfur-doped hard carbon skeleton, can provide an excellent active site for the storage of potassium ions. Ultrasonic intensification significantly reduces the elution time required for neutralization and eliminates the need for a forced increase in elution temperature and rate to improve elution efficiency. In the continuous synthesis process, the recycled chemical activation agent not only does not destroy the activation effect but also has stable activation performance and a good driving force for the growth of activated carbon quality (the specific surface area is 1000 ∼ m2 g−1). Moreover, the sulfur content of the prepared hard carbon anode gradually decreases, whereas its electrical conductivity gradually increases, resulting in an increase in its potassium ions storage capacity. The carbon anode prepared by chemical activation agent after four cycles has a high reversible capacity of 290 mAh g−1 at 0.5 A g−1 and excellent cycling stability (99.5% hold rate at 0.5 A g−1 after 400 cycles). The galvanostatic intermittent titration technique results show that appropriate sulfur content and perfect carbon skeleton structure can promote potassium ions intercalation kinetics. In conclusion, the chemical activation agent cycling strategy can be used to achieve the continuous synthesis of petroleum coke-based potassium ion battery anode.

Bismuth Telluride Nanoplates Hierarchically Confined by Graphene and N-Doped C as Conversion-Alloying Anode Materials for Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) have broad application prospects in the field of electric energy storage systems because of its abundant K reserves, and similar "rocking chair" operating principle as lithium-ion batteries (LIBs). Aiming to the large volume expansion and sluggish dynamic behavior of anode materials for storing large sized K-ion, bismuth telluride (Bi2 Te3 ) nanoplates hierarchically encapsulated by reduced graphene oxide (rGO), and nitrogen-doped carbon (NC) are constructed as anodes for PIBs. The resultant Bi2 Te3 @rGO@NC architecture features robust chemical bond of Bi─O─C, tightly physicochemical confinement effect, typical conductor property, and enhanced K-ion adsorption ability, thereby producing superior electrochemical kinetics and outstanding morphological and structural stability. It is visually elucidated via high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) that conversion-alloying dual-mechanism plays a significant role in K-ion storage, allowing 12 K-ion transport per formular unit employing Bi as redox site. Thus, the high first reversible specific capacity of 322.70mAhg-1 at 50mAg-1 , great rate capability and cyclic stability can be achieved for Bi2 Te3 @rGO@NC. This work lays the foundation for an in-depth understanding of conversion-alloying mechanism in potassium-ion storage.

Edge-nitrogen synergize with micropores to realize fast and durable potassium storage for carbon anode

Edge-N (pyridinic/pyrrolic-N) functionalized carbon is a promising anode for potassium-ion batteries, while micropores have been proven to be effective in increasing capacity and cyclability. However, the obtained carbon materials usually exhibit a low N-doping level and edge-N species based on the conventional pyrolysis method, and the exploration of the synergistic effect of edge-N doping and micropores on the potassium-storage performance is still lacking. Herein, a novel strategy is proposed to prepare edge-N doped carbon (ENC-850) by directly pyrolyzing supermolecule precursors self-assembled by terephthalic acid (BDC) and melamine (MA). Because the s-triazine structure in MA is more stable than BDC, which can easily ensure a higher N-doping content in carbon, and the decomposition of s-triazine structure is accompanied by the release of NCNH2 gas, which enables most doped N-atoms to be of edge-N configurations, favoring the adsorption storage of K-ions. Besides, the released small molecules can create numerous micropores, not only providing active sites, but accommodating volume fluctuation. Therefore, the optimized ENC-850 with the most suitable edge-N content of 60.6% (7.73 at% of total 11.71 at% N-doping) and micropores delivers a high capacity (280 mAh g−1 at 0.5 A g−1) and superior cycling stability (over 2000 cycles).

Organic-Inorganic Hybrid Interfaces Enable the Preparation of Nitrogen-Doped Hollow Carbon Nanospheres as High-Performance Anodes for Lithium and Potassium-Ion Batteries.

An abundant hollow nanostructure is crucial for fast Li+ and K+ diffusion paths and sufficient electrolyte penetration, which creates a highly conductive network for ionic and electronic transport. In this study, we successfully developed a molecular-bridge-linked, organic-inorganic hybrid interface that enables the preparation of in situ nitrogen-doped hollow carbon nanospheres. Moreover, the prepared HCNSs, with high nitrogen content of up to 10.4%, feature homogeneous and regular morphologies. The resulting HCNSs exhibit excellent lithium and potassium storage properties when used as electrode materials. Specifically, the HCNS-800 electrode demonstrates a stable reversible discharge capacity of 642 mA h g-1 at 1000 mA g-1 after 500 cycles for LIBs. Similarly, the electrode maintains a discharge capacity of 205 mA h g-1 at 100 mA g-1 after 500 cycles for KIBs. Moreover, when coupled with a high-mass-loading LiFePO4 cathode to design full cells, the HCNS-800‖LiFePO4 cells provide a specific discharge capacity of 139 mA h g-1 at 0.1 C. These results indicate that the HCNS electrode has promising potential for use in high-energy and environmentally sustainable lithium-based and potassium-based batteries.

Uniformly Dispersed Sb-Nanodot Constructed by In Situ Confined Polymerization of Ionic Liquids for High-Performance Potassium-Ion Batteries

Antimony (Sb) is a potential candidate anode for potassium-ion batteries (PIBs) owing to its high theoretical capacity. However; in the process of potassium alloying reaction; the huge volume expansion (about 407%) leads to pulverization of active substance as well as loss of electrical contact resulting in rapidly declining capacity. Herein; uniformly dispersed Sb-Nanodot in carbon frameworks (Sb-ND@C) were constructed by in situ confined polymerization of ionic liquids. Attributed to the uniformly dispersed Sb-ND and confinement effect of carbon frameworks; as anode for PIBs; Sb-ND@C delivered a superior rate capability (320.1 mA h g−1 at 5 A g−1) and an outstanding cycling stability (486 mA h g−1 after 1000 cycles; achieving 89.8% capacity retention). This work offers a facile route to prepare highly dispersed metal-Nanodot via the in situ polymerization of ionic liquid for high-performance metal-ion batteries

Construction of Ultra-Stable Ultrathin Black Phosphorus Nanodisks Hybridized with Fe3 O4 Nanoclusters and Iron (V)-Oxo Complex for Efficient Potassium Storage.

The practical application of metalloid black phosphorus (BP) based anodes for potassium ion batteries (PIBs) is mainly impeded by its instability in air and irreversible/sluggish potassium -storage behaviors. Herein, w e purposefully conceptualize a two-dimensional composite, where ultrathin BP nanodisks with Fe3 O4 nanoclusters are hybridized with Lewis acid iron (V)-oxo complex (FC) nanosheets (denoted as BP@Fe3 O4 -NCs@FC). The introduced electron coordinate bridge between FC and BP, and hydrophobic surface of FC synergistically assure that BP@Fe3 O4 -NCs@FC is ultra-stable in humid air. With the purposeful structural and componential design, the resultant BP@Fe3 O4 -NCs@FC anode is endowed with appealing electrochemical performance in terms of reversible capacity, rate behavior and long-duration cycling stability in both half and full cells. Furthermore, the underlying formation and potassium-storage mechanisms of BP@Fe3 O4 -NCs@FC w ere tentatively proposed. The in-depth insights here will provide a crucial understanding in rational exploration of advanced anodes for next-generation PIBs. This article is protected by copyright. All rights reserved.

High sulfur-doped microporous carbon for high-rate potassium ion storage: Interspace design and solvent effect

Carbon materials as promising anode for potassium ion batteries (PIBs) suffer from low rate performance, which is attributed to sluggish K+ transport stemming from limited carbon interspace and elusive solvent effect. Herein, interspace design and solvent effect are investigated to resolve this issue. Through an innovative salt template assisted molten sulfur method, large hollow pores, massive micropores and expanded interlayer spacing are integrated in a high sulfur-doped porous carbon (S-PC), showing obviously higher rate capability (351.5 and 122.3 mA h g−1 at 0.1 and 20 A g−1, respectively) than pristine porous carbon (PC). Furthermore, the S-PC exhibits significantly-higher rate performance in ester-based electrolyte (1 M KFSI/EC + DEC) than in ether one (1 M KFSI/DME). Kinetic study demonstrates advantage of interspace design and ester-based electrolyte on promoting faster K+ transport. The explicit solvent effect on S-PC is further examined by XPS and HRTEM analyses, revealing a desirable inorganic KF-salt-dominated, thin solid electrolyte interface (SEI) layer in ester-based electrolyte. This work opens new avenues for precise design of advanced carbon materials for high-rate PIBs.

Hard carbon derived from spent black tea as a high-stability anode for potassium-ion batteries

Hard carbon derived from spent black tea as a high-stability anode for potassium-ion batteries

Design of multifunctional graphene oxide-modified nanofiber film with heterostructure (ZnS-CoS@GO@CNFs) for long-term stable potassium ion storage

When transition metal sulfides are used as high-theoretical-capacity anodes for potassium ion batteries (PIBs), their low conductivity and large volume expansion resulted in inferior rate performance and cyclic stability. In this study, multifunctional graphene oxide (GO) was employed to control the diameter and distribution of nanoparticles within composite fibers, which improved their conductivity and tensile deformation. In addition, a three-dimensional conductive carbon network composed of heterostructures and GO (ZnS-CoS@GO@CNFs) accelerated the kinetics and stabilized potassium ion storage. As the anode material of PIBs, the composite provided an excellent rate performance of 210 mA h g−1 at 3 A g−1, and after 2800 cycles under a large current of 2 A g−1, the capacity retention rate was 97.7% (171 mA h g−1). Furthermore, when the nanofiber film was used as a self-supporting anode, it maintained a stable capacity output (302 mA h g−1 after 100 cycles at 0.1 A g−1). A foldable pouch cell was assembled using a potassium ion hybrid super-capacitor, and it was found to operate safely and normally under multiangle repeated bending and final recovery; further, it provided a high energy density (134 W h kg−1) and power density (5815 W kg−1). The excellent electrochemical properties determined here further reveal the application prospects of multifunctional GO composite fiber film.

Mesoporous N,S‐Rich Carbon Hollow Nanospheres Controllably Prepared From Poly(2‐aminothiazole) with Ultrafast and Highly Durable Potassium Storage

AbstractCarbon with few active sites and narrow interlayer distance as anode for potassium ion batteries (PIBs) always shows low capacity, sluggish kinetics, and low Columbic efficiency. Herein, poly(2‐aminothiazole) (P2AT) hollow nanospheres are first synthesized as a carbon source for high N, S co‐doped carbon hollow nanospheres (NS‐HCSs). The hollow P2AT nanospheres can be controllably synthesized with an Ostwald ripening process. The unique doping and structure endow the NS‐HCSs with high content of N and S dopants in carbon, mesoporous structure with enlarged interlayer distance, elevated ratio of N‐6 and N‐5 species, enhanced conductivity, abundant surface defects, and large active sites. When evaluated as an anode for PIBs, NS‐HCSs exhibit a high reversible capacity of 422 mAh g‒1 and excellent long‐term cycling performance. Using combined experiment and theoretical computation, including in situ TEM and in situ Raman, the K‐storage mechanism and dynamic evolution processes of NS‐HCSs, including low volume expansion, enhanced K‐ion adsorption, and stable composition and structure evolution during repeating potassiation/de‐potassiation processes is revealed. This quantitative design for highly durable K‐storage and large capacity in carbon can be advantageous for the rational design of anode materials of PIBs with ideal electrochemical performance.

A plastics-derived organic anode material for practical and sustainable potassium-ion batteries

Organic electrode materials are of particular interest for storing large-size potassium ions. Herein, we demonstrate that polyethylene terephthalate (PET), a synthetic organic polymer with functional carbonyl groups, could deliver a two-electron redox mechanism for potassium storage. The PET particles, synthesized from PET plastic film by a simple solvent thermal method, achieve almost complete utilization of redox-active sites, providing a reversible capacity of 273 mAh/g. Over 800 cycles of cycling life are demonstrated by the PET, along with fast K+-transport kinetics and thus outstanding rate performance. Furthermore, a fabricated full cell composed of PET anode can provide a high operating voltage of 3.17 V with a high energy density of 245 Wh/kg. This study offers a new way to utilize PET plastic waste and guide the development of organic anode for low-cost potassium-ion batteries.

Chemical prepotassiation enabling high-efficiency and long-life alloy anodes for potassium-ion batteries

Using high-capacity alloy anodes can grandly advance potassium-ion batteries. However, one common issue plaguing these anodes is the loss of active K+ ions associated with persistent side reactions on unstable electrode-electrolyte interfaces, resulting in low initial Coulombic efficiency (ICE) and shortened cycling life. Herein, we first explore the potential of a solution-based potassiation reagent (potassium-biphenyl in dimethoxyethane, K-Bp/DME) for chemical prepotassiation. With a low redox potential of 0.45 V vs. K+/K, the K-Bp/DME solution can readily pre-storing K+ ions into various alloy-type anodes by a simple immersion operation in a few minutes. Taking nanostructured Bi/P/CNT composite as an example, we demonstrate that the K-Bp/DME prepotassiation simultaneously enables the notable ICE improvement (from 51.9% to 96.2%) and long-life cycling (running 700 cycles at 1.5 A g−1 with a tiny capacity attenuation rate of 0.031% per cycle) by forming a KF-rich SEI film. Furthermore, the full cell assembled by coupling the prepotassiated Bi/P/CNT anode with a potassium Prussian blue cathode delivers a desirable ICE of 88.6% and superior capacity retention of 75.3% after 450 cycles at 0.3 A g−1. Besides, this prepotassiation method is also successfully extended to other anodes (Sb and Sn), indicating its general applicability.

Pseudocapacitive Potassium-Ion Intercalation Enabled by Topologically Defective Soft Carbon toward High-Rate, Large-Areal-Capacity, and Low-Temperature Potassium-Ion Batteries.

Carbonaceous materials are widely investigated as anodes for potassium-ion batteries (PIBs). However, the inferior rate capability, low areal capacity, and limited working temperature caused by sluggish K-ions diffusion kinetics are still primary challenges for carbon-based anodes. Herein, a simple temperature-programmed co-pyrolysis strategy is proposed for the efficient synthesis of topologically defective soft carbon (TDSC) based on inexpensive pitch and melamine. The skeletons of TDSC are optimized with shortened graphite-like microcrystals, enlarged interlayer spacing, and abundant topological defects (e.g., pentagons, heptagons, and octagons), which endow TDSC with fast pseudocapacitive K-ion intercalation behavior. Meanwhile, micrometer-sized structure can reduce the electrolyte degradation over particle surface and avoid unnecessary voids, ensuring a high initial Coulombic efficiency as well as high energy density. These synergistic structural advantages contribute to excellent rate capability (116mAhg-1 at 20 C), impressive areal capacity (1.83mAhcm-2 with a mass loading of 8.32mg cm-2 ), long-term cycling stability (capacity retention of 91.8% after 1200h cycling), and low working temperature (-10°C) of TDSC anodes, demonstrating great potential for the practical application of PIBs.

Three-dimensional bacterial cellulose and MOF-74 derivatives as anode for high performance potassium-ion batteries

In this paper, we synthesized a three-dimensional hierarchical structure through simple hydrothermal combining pyrolysis method, which mainly encapsulated 0D Fe3N and Fe2O3 nanoparticles in 1D carbon nanotubes, which could be evenly grafted onto 2D bacterial cellulose (BC) carbon matrix, denoted as [email protected]2O3/Fe3N-CNT. As an anode material, the composite showed excellent electrochemical performance both in potassium ion battery (PIBs) and sodium ion battery (SIBs). Specifically, after 200 cycles at a current density of 100 mA g−1, it showed discharge capacity of 342.2 mAh g−1 and 420.6 mAh g−1 in PIBs and SIBs, respectively. The excellent performance is mainly due to the particularity of the hierarchical structure. The hierarchical limitation of the low dimensional structure to the high dimensional structure can effectively buffer the volume expansion caused by the ion deinterleaving process, and PBC is conducive to the structural stability of the material. In addition, the "tip growth method" successfully achieved the in-situ growth of N-doped carbon nanotubes (CNT), which not only avoids the agglomeration of nanoparticles to a certain extent, but also improves the conductivity of the material and promotes ion transport. This work provides ideas for exploring other carbon-based composites to realize high-performance metal ion batteries.