Anode Material For Potassium-ion Batteries Research Articles

Research progress of biomass carbon materials as anode materials for potassium-ion batteries.

Biochar materials have attracted people's attention because of their environmental friendliness, abundant resources, and the use of waste resources for reuse. As a potassium-ion anode material, biomass char materials synthesized by different methods have broad application prospects. However, due to the problems of low initial magnification and limited potassium-storage capacity, it is necessary to improve the electrochemical performance through modifications, such as atomic doping. Atomic doping is an effective way to improve battery conductivity and potassium storage. In this paper, the synthesis method of biochar as an anode material for potassium-ion batteries and the influence of atomic doping on its modification in recent years are reviewed.

ZIF-67-derived Co/CoSe ultrafine nanocrystal Schottky heterojunction decorated hollow carbon nanospheres as new-type anodes for potassium-ion batteries

Metal-organic frameworks (MOFs) have the advantages of controllable chemical properties, rich pore structures and reaction sites and are expected to be high-performance anode materials for the next generation of potassium-ion batteries (PIBs). However, due to the large radius of potassium ions, the pure MOF crystal structure is prone to collapse during ion insertion and processing, so its electrochemical performance is quite limited. In this work, a hollow carbon sphere-supported MOF-derived Co/CoSe heterojunction anode material for potassium-ion batteries was developed by a hydrothermal method. The anode has high potassium storage capacity (461.9 mA h/g after 200 cycles at 1 A/g), excellent cycling stability and superior rate performance. It is worth noting that the potassium ion storage capacity of the anode material shows a gradual upward trend with the charge–discharge cycle, which is 145.9 mA h/g after 3000 cycles at a current density of 10 A/g. This work demonstrates that MOF-derived CoSe anodes with high capacity and low cost may be promising candidates for the introduction of potassium ion storage.

Hollow CuSbSy Coated by Nitrogen-Doped Carbon as Anode Electrode for High-Performance Potassium-Ion Storage

As a potential anode material for potassium-ion batteries (PIBs), bimetallic sulfides are favored by researchers for their high specific capacity, low cost, and long cycle life. However, the non-ideal diffusion rate and poor cycle stability pose significant challenges in practical applications. In this work, bimetallic sulfide CuSbSy@C with a yolk-shell structure was synthesized by in situ precipitation and carbonization. When CuSbSy is applied in the anode of PIBs, it can provide the desired capacity and reduce the volume expansion of the compound through the synergistic effect between copper and antimony. At the same time, the existence of the nitrogen-doped carbon shell confines the material within the shell while improving its electrical conductivity, inhibiting its volume expansion and aggregation. Therefore, CuSbSy@C exhibits a satisfactory capacity (438.8 mAh g−1 at 100 mA g−1 after 60 cycles) and an excellent long cycle life (174.5 mAh g−1 at 1000 mA g−1 after 1000 cycles).

Vapor-phase derived ultra-fine Bismuth nanoparticles embedded in carbon nanotube networks as anodes for sodium and potassium ion batteries

Bismuth (Bi) is a promising material as the anode for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to its characteristics such as reasonable price and high theoretical volumetric capacity (3800 mAh cm−3). Nevertheless, considerable drawbacks have hindered the practical applications of Bi, including its relatively low electrical conductivity and inevitable volumetric change during the alloying/dealloying processes. To solve these problems, we proposed a novel design:Bi nanoparticles were synthesized via a single-step low-pressure vapor-phase reaction and embedded onto the surfaces of multi-walled carbon nanotubes (MWCNTs). After being vaporized at 650℃ and 10-5 Pa, Bi nanoparticles less than 10 nm were uniformly distributed in the three-dimensional (3D) MWCNT networks to form a Bi/MWNTs composite. In this unique design, the nanostructured Bi can reduce the risk of structural rupture during cycling, and the structure of the MWCMT network is beneficial in shortening the electron/ion transport path. In addition, MWCNTs can improve the overall conductivity of the Bi/MWCNTs composite and prevent particle aggregation, thus improving the cycling stability and rate performance. As an anode material for SIB, the Bi/MWCNTs composite has demonstrated excellent fast charging performance with a reversible capacity of 254 mAh/g at 20 A/g. A capacity of 221mAhg−1 after cycling at 10 A/g for 8000 cycles has also been achieved for SIB. As an anode material for PIB, the Bi/MWCNTs composite has delivered excellent rate performances with a reversible capacity of 251 mAh/g at 20 A/g. A specific capacity of 270mAhg−1 after cycling at 1Ag−1 for 5000 cycles has also been achieved for PIB.

High-entropy NaCl-type metal chalcogenides as K-ion storage materials: role of the cocktail effect

The drastic volume expansion of active materials and the shuttle effect of polychalcogenides hindered the development of anode materials for potassium-ion batteries (PIBs). Thus, various strategies have been used to overcome the negative effects associated with potassiation. Here, we propose a NaCl-type high-entropy metal chalcogenide (HEMC) prepared using a simple melting method as an anode material for PIBs. Unlike traditional high-entropy materials comprising inactive metals, NaCl-type HEMCs can realize the occupancy of cationic sites by active metals. We show that AgSnSbSe1.5Te1.5, a HEMC, produces short-range tiny cells during phase-change energy storage reactions, reconciling the participation of active and inactive metals to form various heterointerfaces and different functional metal nanoparticles. The kinetic and density functional theory analysis showed that the formation of heterointerfaces decreased the diffusion energy barrier of K+ and the inactive metal silver provided appropriate adsorption energy, suppressing the latent shuttle effect. The results show enhanced electrochemical performance owing to the elemental composition of high-entropy materials and the formation of tunable heterointerfaces and functional nanoparticles in electrochemical reactions, offering a new concept for the design of PIB anode materials.

SnTe nanoparticles physicochemically encapsulated by double carbon as conversion-alloying anode materials for superior potassium-ion batteries

Telluride tin (SnTe) is a promising conversion-alloying anode for potassium-ion batteries (PIBs) due to its high theoretical specific capacity induced by multi-electron transport reaction and low operating voltage, whereas huge volume expansion and poor kinetics behavior become key scientific bottleneck limiting the battery performances. Herein, SnTe nanoparticles physicochemically wrapped by graphene and nitrogen-doped carbon (SnTe@rGO@NC) are proposed as anode materials for PIBs. The pre-electrostatic interaction urges the formation of Sn-C and Te-C chemical bonds between SnTe and double carbon to strengthen the interfacial stability and electron transfer, and the conductive architecture with hierarchical encapsulation effect is beneficial to maintaining the electrode integrity and electrochemical dynamics. It is demonstrated from first principles calculations and experimental results that SnTe@rGO@NC contributes fast electron transmission, strong K-ion adsorption, and superior K-ion diffusion capability. Ex-situ characterizations uncover that SnTe undergoes conversion-alloying dual-mechanism with the products of K2Te and K4Sn23 replied on Sn redox site (23SnTe + 50K+ + 50e– ↔ K4Sn23 + 23K2Te). Thus, the SnTe@rGO@NC electrode delivers a high initial charge specific capacity of 243.9 mAh g–1 at 50 mA g–1, superior rate performance (112.6 mAh g–1 at 1.0 A g–1), and outstanding cyclic stability at various current densities.

Highly active and stable Cu9S5-MoS2 heterostructures nanocages enabled by dual-functional Cu electrocatalyst with enhanced potassium storage

• Cu 9 S 5 /MoS 2 hollow nanocage heterostructure was studied as anode material for potassium-ion batteries. • Rational introduced Cu 0 intermediates effectively anchor K x S y polysulfides and facilitate rapid charge transfer. • Unique Cu 9 S 5 /MoS 2 nanocage showed superior conversion reaction reversibility in K-storage application. The intrinsic poor electrical conductivity, severe dissolution of K x S y intermediates, and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides (TMDs) anode for potassium-ion batteries (PIBs). Herein, a rationally designed Cu 9 S 5 /MoS 2 /C heterostructure hollow nanocage was synthesized with assistance from metal-organic frameworks (MOFs) precursor. During the K-storage process, the homogeneously distributed the sulfiphilic nature of Cu 0 reaction product could act as a dual-functional catalyst, not only facilitating the rapid charge transfer but also effectively anchoring (K x S y ) polysulfides, thus boosting K-storage reactions reversibility during the conversion reaction process. When applied as an anode for PIBs, the as-prepared heterostructure exhibits excellent reversible capacity and long cycle lifespan (350.5 mAh g –1 at 0.1 A g –1 and 0.04% per cycle capacity decay at 1 A g –1 after 1000 cycles). Additionally, the potassium storage mechanism is distinctly revealed by in-situ characterizations. The nanoarchitecture designing strategy for the advanced electrode in this work could provide vital guidance for relevant energy storage materials. The hollow Cu9S5/MoS2/C nanocage has been rational designed and regarded as an anode material for potassium-ion batteries (PIBs). Due to the dual-functional catalytic effects of in-situ formed Cu0 nanograin during conversion reaction and homogeneously distributed heterointerfaces within Cu9S5/MoS2, the poor charge transfer, severe dissolution of KxSy polysulfides, and inferior phase transformation reaction reversibility can be significantly improved. It can not only strengthen the integral stability, but also enhance the K-storage properties with long-life and high-capacity.

KOH-treated mesocarbon microbeads used as high-rate anode materials for potassium-ion batteries

AbstractGraphite is one of the most promising anode materials for potassium-ion batteries (PIBs) due to its low cost and stable discharge plateau. However, its poor rate performance still needs to be improved. A novel graphitic anode was designed from commercial mesocarbon microbeads (MCMBs) by KOH treatment. Using limited oxidation and slight intercalation, the interlayer spacing of graphitic layers on the surface of the MCMBs was increased, causing the K+ diffusion rate to be significantly improved. When this modified material was combined with carboxymethyl cellulose as a binder (79.2%) and used as a PIB anode, it had a high plateau capacity below 0.25 V (271 mAh g−1), superior rate capability (160 mAh g−1 at 1.0 A g−1), excellent cycling stability (about 184 mAh g−1 after 100 cycles at 0.1 A g−1), and a high initial coulombic efficiency. This work provides a simple strategy to prepare graphitic materials with an excellent potassium storage performance.

Sulfur and phosphorus co-doped hard carbon for potassium ion storage

Due to the low cost, good chemical stability and structural diversity, hard carbon has been considered as an important anode material for potassium-ion batteries (PIBs). However, due to the large diameter of K+, PIBs with both excellent rate performance and long-life is still challenging. Herein, sulfur (S), phosphorus (P) co-doped hard carbon anode are synthesized via polymerization of thiophene and phytic acid and the following concise pyrolysis strategy. S in hard carbon can used as reactive sites for K+ storage and P doping will effectively improve wettability of electrolyte. After temperature regulation, the fabricated SP-700 with dual and abundant heteroatom doping exhibits high initial reversible capacity (412 mAh g−1 at 0.05 A g−1), excellent rate performance (130 mAh g−1 at 5 A g−1) and stable cyclic performance (94 mAh g−1 after 1500 cycles at 2 A g−1).

Bi/Bi3Se4 nanoparticles embedded in hollow porous carbon nanorod: High rate capability material for potassium-ion batteries

Considering their superior theoretical capacity and low voltage plateau, bismuth (Bi)-based materials are being widely explored for application in potassium-ion batteries (PIBs). Unfortunately, pure Bi and Bi-based compounds suffer from severe electrochemical polarization, agglomeration, and dramatic volume fluctuations. To develop an advanced bismuth-based anode material with high reactivity and durability, in this work, the pyrolysis of Bi-based metal–organic frameworks and in-situ selenization techniques have been successfully used to produce a Bi-based composite with high capacity and unique structure, in which Bi/Bi3Se4 nanoparticles are encapsulated in carbon nanorods (Bi/Bi3Se4@CNR). Applied as the anode material of PIBs, the Bi/Bi3Se4@CNR displays fast potassium storage capability with 307.5 mA h g−1 at 20 A g−1 and durable cycle performance of 2000 cycles at 5 A g−1. Notably, the Bi/Bi3Se4@CNR also showed long cycle stability over 1600 cycles when working in a full cell system with potassium vanadate as the cathode material, which further demonstrates its promising potential in the field of PIBs. Additionally, the dual potassium storage mechanism of the Bi/Bi3Se4@CNR based on conversion and alloying reaction has also been revealed by in-situ X-ray diffraction.

Revealing the evolution of doping anions and their impact on K-Ion storage: A case study of Se-doped In2S3

Anion doping has been proven to be an effective way to enhance the rate capability and cyclability of conversion-type anode materials for lithium-ion/sodium-ion batteries. However, it is still a burgeoning methodology in potassium-ion batteries. In addition, the evolution of doping anions and their impact on the K+ storage during the conversion reaction are indeterminate. Herein, Se anions are purposefully doped into a model conversion-type In2S3@C anode material, which is labeled as In2S3–xSex@C. Elaborate analytical techniques and theoretical simulations reveal that Se doping regulates the electronic structure and weakens the bonding strength of In2S3–xSex, resulting in fast K+ intercalation and high conversion reactivity. The advantages of Se doping can be maintained upon the whole cycling because Se exists in the form of doping after potassiation (doped into K2S: K2S1–x/3Sex/3) and depotassiation (re-doped into In2S3: In2S3–xSex), which is proved by various electrochemical analyses and ex-situ observations. Therefore, In2S3–xSex@C exhibits a high reversible capacity (709 mA h g–1 at 0.1 A g–1) and excellent cyclability (118 mA h g–1 at 10.0 A g–1 after 1000 cycles). Moreover, full cells with the In2S3–xSex@C anode achieve a satisfying energy density of 146 Wh kg–1. This work provides a new guideline for designing advanced anion-doping conversion-type anode materials of potassium-ion batteries.

Nitrogen-Doping-Induced High-Performance Carbon Nanofiber Anodes for Potassium-Ion Storage

Due to the abundant supply of potassium, potassium-ion batteries (PIBs) are considered as a promising alternative battery system to lithium-ion batteries (LIBs). Carbonaceous materials are the preferred anode materials for these batteries. However, the electrochemical performance of carbonaceous anode materials is still unsatisfactory, hindering the development of PIBs. In this work, nitrogen-doped carbon nanofibers (N-CNFs) were synthesized by the calcination of bacterial cellulose with urea acting as a nitrogen source. When employed as an anode material for PIBs, the N-CNFs exhibit a stable specific capacity of 205 mA h g–1 at 0.2 C after 250 cycles and an outstanding rate capability of 149.7 mA h g–1 at 5.0 C. The N-doped structure can facilitate the K+ and electronic conductivity, which will effectively enhance electrochemical performance of the electrode. In addition, ex situ X-ray photoelectron spectroscopy and X-ray diffractometry pattern analyses illustrate the reversible insertion of K+ in the N-CNF electrode.

Bagasse-Derived Hard Carbon Anode with an Adsorption–Intercalation Mechanism for High-Rate Potassium Storage

Hard carbon is a kind of abundant-resource and cost-effective anode material for potassium-ion batteries to realize commercialization shortly. However, the poor rate performance and ambiguous energy storage mechanism of hard carbon remain great bottlenecks. In this study, bagasse-pyrolyzed hard carbon (BC) is prepared by the pyrolysis of bagasse, which exhibits a larger surface area and better electrical conductivity than sugarcane-pyrolyzed hard carbon (SC). The BC exhibits a high reversible capacity of 235 mAh g–1 at 100 mA g–1 and a high rate (161 mAh g–1 at 1000 mA g–1) for K+ storage, which are better than those of SC (108 mAh g–1 and 49 mAh g–1). In situ X-ray diffraction and Raman results reveal the “adsorption–intercalation” K+ storage mechanism and prove that the favorable defects endow BC with better electrochemical capability.

Bi@Bi2O3 anchored on porous graphene prepared by solvothermal method as a high-performance anode material for potassium-ion batteries

To enhance potassium storage performance of graphene, in situ formed electroactive bismuth nanoparticles were introduced into the porous graphene. The Bi@Bi2O3/graphene composites, which possess the special microstructure that Bi nanoparticles are coated by Bi2O3 and attached to the porous graphene, was synthesized via an environmental-friendly and simple solvothermal method combined with high-temperature sintering under inert environment using graphene oxide, BiCl3 and ethanol as raw materials. Benefiting from the special microstructure and synergistic effect of nano-bismuth particles and graphene, Bi@Bi2O3/graphene composites display better electrochemical performance than graphene. Between 0.01 and 3.0 V (vs K+/K), the electrode was galvanostatically discharged/charged at 100 mA g−1 and the optimal Bi@Bi2O3/graphene composite (Bi@Bi2O3/G-50) has large initial charge capacity (886.4 mAh g−1), which is significantly larger than the theoretic capacities of Bi (385 mAh g−1) and graphene (279 mAh g−1), and after 100 cycles, the high remaining charge capacity of 466.4 mAh g−1 for Bi@Bi2O3/G-50 was obtained. While the remaining charge capacity of graphene is only 112 mAh g−1 after 100 cycles. When electrode cycled at high current density of 800 mA g−1, the initial charge capacities of Bi@Bi2O3/G-50 and graphene are 294.1 and 130 mAh g−1, respectively, and the corresponding remaining capacities are 179.1 and 67.1 mAh g−1, respectively. The results imply that the introduction of high-capacity electroactive materials and the design of special microstructures are effective strategies to significantly improve the potassium storage performance of carbon-based anode materials for potassium-ion batteries.

A comprehensive review of carbon anode materials for potassium-ion batteries based on specific optimization strategies

This review mainly focuses on the discussion of mechanisms behind improved potassium storage properties, starting from some specific optimization strategies, and presents a perspective for the further development of carbon anodes.

Rational construction of VSe2encapsulated in selenized polyacrylonitrile toward a high-rate capacity and wide temperature tolerance for potassium-ion batteries

Metal selenides are considered potential anode materials for potassium-ion batteries (PIBs) because of their decent theoretical capacity and abundant energy reserves.

State-of-art progress and perspectives on alloy-type anode materials for potassium-ion batteries

The state-of-art progress of alloy-type anodes for potassium-ion batteries and their K+ storage mechanism and structure-property relationship are summarized.

Recent progress on alloy-based anode materials for potassium-ion batteries

Microstructures is an international peer-reviewed, open access, online journal. The journal of Microstructures publishes articles covering new research and developments, perspectives, and reviews related to the microstructures of materials, including, but not limited to metals and alloys, ceramics, polymers, composites, crystals, glasses, biomaterials, interfaces and nanomaterials.

Reasonable intrinsic microstructure of microcrystalline graphite for high-rate and long-life potassium-ion batteries

Carbon materials, including non-graphite carbon and graphite have been extensively studied as anode materials for Potassium-ion batteries (PIBs). However, due to the slow kinetics of potassiation, it is still challenging to obtain anode materials with rate capability, good stability and low price. Microcrystalline graphite (MG) possesses ordered graphene layers and abundant interparticle voids and correspondingly undergoes a surface adsorption behavior at first and then the intercalation of K+ at low potential, which is conductive to high energy density. In addition, the larger interplanar spacing of MG with suitable crystalline size can stand for the fluctuation of interlaminar spacing caused by repeated K+ bombardment because strain in such structure can be relaxed due to sufficiently available free space. When used as anode material of PIBs, microcrystalline graphite can deliver a high reversible capacity of 249 mAh g−1 at 100 mA g−1 after 100 cycles in a readily-available electrolyte of 0.8 M KPF6 in EC/DEC (1:1 vol%), which offer a significant cost-saving opportunity. Furthermore, compared to flake graphite and soft carbon, MG exhibits the highest capacity of 139 mAh g−1 at 500 mA g−1 after 500 cycles. Our investigations will greatly promote the MG's industrial development in China.

Ti3C2/fluorine-doped carbon as anode material for high performance potassium-ion batteries

Potassium ion batteries (PIBs) attract increasing attention due to abundant natural storage of potassium resources in the earth’s crust, low cost, and high operating potential. However, larger radius of K+ compared to Na+/Li+, poor kinetics and unstable structure lead to inferior electrochemical performance for PIBs. Herein, we propose 3D fluorine-doped carbon@Ti3C2 MXene (3D FC@Ti3C2) composite as anode material for PIBs. In the composite, coating carbon can protect Ti3C2 from oxidation and self-stack, fluorine-doped carbon can afford more defects and introduce numerous active site that can strongly adsorb K+. In addition, the composite can enlarge the interlayer spacing, and the 3D interconnected carbon framework can enhance conductivity and alleviate the volume expansion during cycling. Benefiting from these synergetic effects, the 3D FC@Ti3C2 can obtain supernormal electrochemical property with high capacity of 288 mAhg−1 at 100 mAg−1 after 200 cycles and extraordinary cyclic stability of 174 mAhg−1 at 500 mAg−1 after 1000 cycles.