Metal chalcogenides (MCs) have emerged as promising candidates for potassium ion battery (KIB) anode materials, yet the sluggish redox kinetics and notorious shuttle effect inescapability lead to inferior rate performance and poor cyclability. Herein, a P-doped PbTe/MXene (P-PbTe/MXene) superstructure is rationally constructed by decorating PbTe on MXene via a hydrothermal reaction and followed by bifunctional P-doping, where P heteroatoms enter both PbTe and MXene lattice. The P-PbTe/MXene anode shows enhanced reaction kinetics and suppressed shuttle effect of polytellurides due to the enhanced chemical adsorption stemming from the low energy gaps between the d-band center and the p-band center of P-MXene. As a result, the P-PbTe/MXene superstructure shows superior potassium storage properties, including high reversible capacity (289.1 mAh g-1 at 0.2 A g-1 after 200 cycles), outstanding rate performance (151.3 mAh g-1 at 20 A g-1), and ultrastable cyclability (180.1 mA h g-1 at 2.0 A g-1 after 2000 cycles) in half battery. Also, the P-PbTe/MXene anode exhibits high energy density (186.0 Wh kg-1 at 0.1 A g-1) and excellent bending stability in soft-package full cells.

The pursuit of high-energy-density lithium-ion batteries has driven extensive research into ultra-high nickel cathode materials, which enhance the capacity but often face challenges with structural stability and cycling performance. Boron (B) doping was employed to enhance the cycling stability, but sacrifices the initial and subsequent capacity. Here, we report a feasible and novel approach to redeem this capacity loss of ultra-high nickel cathode materials (LiNi0.98Co0.02O2) via elevated sintering temperature. Our study reveals that B doping significantly impacts crystal growth, resulting in reduced crystallinity, refined primary grain size, and increased degree of Li/Ni cation mixing, and hence in the improved cycling stability but remarkably decreased initial capacity. Increasing the sintering temperature of B-doped samples can recover the initial capacity loss while preserving better cycling stability compared to undoped samples. The detailed mechanism is analyzed by in-situ XRD, FIB-TEM, and extensive electrochemical methods. Our study provides new insights and proposes strategies for balancing initial capacity and cycle stability in ultra-high nickel cathode materials.

The mechanism of peroxymonosulfate (PMS)-based systems in the treatment of organic wastewater has been extensively studied; however, the protonation process has received comparatively less attention. In this work, we introduce Sr-doped LaMnO3 as models for investigating the protonation pathway. Despite exhibiting a higher Mn4+ content, fewer oxygen vacancies, and lower surface acidity than LaMnO3-delta (LMO)-characteristics that are typically unfavorable for PMS adsorption-the La0.5Sr0.5MnO3-delta (LSM) demonstrates superior degradation activity towards bisphenol A. Notably, reactive oxygen species (ROS) contribute minimally to the degradation efficiency in the LSM/PMS system; rather, the predominant mechanism is the direct oxidation process (DOP) facilitated by protonation. The upshifted O p-band center in LSM enhances the adsorption of H+ released from PMS, while the strengthened Mn-O covalency accelerates electron transfer. The PMS- and H2SO4-based systems are differentiated via electrochemical methods and mini-quantity experiments, validating that the PMS-involved system could provide additional oxidation capacity accompanied by the protonation process. This study elucidates the direct oxidation pathway in PMS-based systems, paving the way for more effective strategies in wastewater remediation.

The design and fabrication of bifunctional catalysts with high electrocatalytic activity and stability are critical for developing highly reversible Li-O2 2 batteries (LOBs). Herein, the N, P co-doped MXene (NP-MXene) is prepared by one-step annealing method and evaluated as bifunctional catalyst for LOBs. The results suggest that the P doping plays a crucial role in increasing interlayer distance of MXene, thereby effectively providing more active sites, fast mass transfer, and ample space for the deposition/decomposition of Li2O2. 2 O 2 . Moreover, the N doping can significantly elevate the d-band center of Ti, thereby remarkably improving the adsorption of reaction intermediates and accelerating the deposition/decomposition of Li2O2 2 O 2 films. Consequently, the MXene-based LOBs deliver an ultrahigh specific capacity of 13,995 mAh/g at 500 mA g- 1 , a discharge/charge voltage gap of 0.89 V, and a cycle life up to 523 cycles with a limited capacity of 1000 mAh/g at 500 mA g- 1 . Impressively, the as- fabricated flexible LOBs with NP-MXene cathode display excellent cycling stability and ability to continuously power LEDs even after bending. Our findings pave the road of heteroatom doped MXenes as next-generation electrodes for high-performance energy storage and conversion systems.

With increasing global energy demand and stricter environmental protection requirements, energy storage technology has become a research hotspot in the global energy field. New types of energy storage devices continue to emerge owing to the continuous development of cost-effective energy storage technology. Among them, potassium-ion batteries have received widespread attention as a new type of alkali metal ion battery because of their high capacity and low cost and are considered one of the future development directions. However, the research on potassium-ion batteries is still in its infancy, with many challenges to overcome regarding practical applications. A key factor affecting the performance of potassium-ion batteries is the anode material, as it not only affects the manufacturing costs but also directly affects the power density and energy density of the battery. Traditional anode materials for lithium-ion batteries cannot meet the requirements of potassium-ion batteries. Therefore, developing high-performance anode materials suitable for potassiumion batteries is an important research direction at present. The charge and discharge rate and cycling life of potassium-ion batteries also need further improvements. Currently, the low-rate performance, short cycle life, and unsatisfactory practical capacities limit their practical application and commercialization. However, the future of potassium-ion batteries remains promising. Upon resolving the aforementioned issues, potassium-ion batteries will have diverse application prospects, such as electric vehicles, energy storage stations, and smart grids, providing important support for solving energy problems. Therefore, the research and development of potassium-ion batteries are an important direction in the global energy field. Current research efforts are primarily focused on exploring novel anode materials with exceptional ratability and cyclability. In this regard, we synthesized a new type of anode material based on bismuth telluride (Bi2Te3) and experimentally studied its applicability in potassium-ion batteries. The performance of Bi2Te3 anode for potassium-ion batteries has been limited by its structural instability and slow electrochemical reaction kinetics. In this study, rod-like Bi2Te3 was grown on accordion-like MXene, followed by P-doping to obtain a high-performance P-Bi2Te3/MXene superstructure. This novel anode had abundant Te vacancies and good self-auto adjustable function, providing excellent cycling stability (323.1 mAh.g(-1) after 200 cycles at 0.2 A.g(-1)) and outstanding rate capability (67.1 mAh.g(-1) at 20 A.g(-1)). Kinetic analysis and ex situ characterization indicate that the superstructure exhibits superior pseudocapacitive properties, high electrical conductivity, favorable diffusion capability, and reversible insertion and conversion reaction mechanism.

Developing highly efficient catalysts for the hydrogen evolution reaction (HER) is crucial for advancing renewable hydrogen energy technologies. Heterophase nanomaterials have shown great promise in catalysis, owing to the synergistic effect among various phases and the abundance of active sites located at the phase boundaries or interfaces. However, achieving precise control over these phase structures during synthesis remains a significant challenge. In this work, we explored a one-pot synthesis method for amorphous/crystalline heterophase Rh nanoparticles, with crystallinity tunable by adjusting the quantity of urea and reaction duration. Due to the increased electrochemical active sites, enhanced electron transport, the resulting amorphous/crystalline heterophase Rh exhibits superior HER activities in both acidic (with an overpotential of 27 mV) and alkaline media (with an overpotential of 21 mV), surpassing that of commercial Pt/C and crystalline Rh. Theoretical calculations indicate that the amorphous/crystalline structure reduces the kinetic barrier for water splitting and optimizes adsorption free energy of hydrogen (Delta GH*), thereby enabling the catalyst to exhibit significantly enhanced HER performance. This exploration offers a valuable reference for designing amorphous/ crystalline heterophase structures and demonstrates the great potential of phase engineering strategy in the development of electrocatalysts.

Garnet based solid-state electrolyte Li6.75La3Zr1.75Ta0.25O12 (LLZTO) is one of the most promising electrolytes for advanced all-solid-state lithium batteries. However, the ceramic electrolyte is difficult to densify under normal sintering conditions, and hence the Li+ transportation via grain boundary is significantly limited by the loose contact between electrolyte granules, resulting in a high Li+ ionic impedance. Herein, we report a novel 2-step approach to obtain a relatively dense LLZTO ceramic pellet by a special Al-doping method, in which the Al was derived from the erosion of the corundum milling beads by LiOH during ball milling. This approach enables the simultaneous distribution of the aluminum (Al) within the LLZTO lattice and uniformly within the grain boundary, serving as a sintering aid, effectively boosts the fusion of grain boundary and reduced the failure rate during the sintering process. The ceramic pellet had a conductivity of 8.13 x 10(-4) S cm(-1), higher than that without Al-doping or using Al2O3 as dopant. This method provides an easier way to sinter the garnet ceramic electrolyte.

The pursuit of anode materials capable of rapid and reversible potassium storage performance is a challenging yet fascinating target. Herein, a heterointerface engineering strategy is proposed to prepare a novel superstructure composed of amorphous/crystalline Re2Te5 anchored on MXene substrate (A/C-Re2Te5/MXene) as an advanced anode for potassium-ion batteries (KIBs). The A/C-Re2Te5/MXene anode exhibits outstanding reversible capacity (350.4 mAh g-1 after 200 cycles at 0.2 A g-1), excellent rate capability (162.5 mAh g-1 at 20 A g-1), remarkable long-term cycling capability (186.1 mAh g-1 at 5 A g-1 over 5000 cycles), and reliable operation in flexible full KIBs, outperforming state-of-the-art metal chalcogenides-based devices. Experimental and theoretical investigations attribute this high performance to the synergistic effect of the A/C-Re2Te5 with a built-in electric field and the elastic MXene, enabling improved pseudocapacitive contribution, accelerated charge transfer behavior, and high K+ ion adsorption/diffusion ability. Meanwhile, a combination of intercalation and conversion reactions mechanism is observed within A/C-Re2Te5/MXene. This work offers a new approach for developing metal tellurides- and MXene-based anodes for achieving stable cyclability and fast-charging KIBs.

Graphite is one of the major anode materials for commercial lithium-ion batteries. Li+ transport in a single graphite granule along intra and interlayer modes is a crucial factor for the battery performance. However, direct evidence and visualized details of the Li+ transports are hardly provided. Here, we report the direct observation of the anisotropic transport behavior of Li+ and investigate the electro-chemo-structure evolution during the lithiation of graphite through both the intra and interlayer pathways via in situ transmission electron microscopy. The in situ experiments of nano batteries give two extreme conditions, in which thermal runaway induced by polarization only occurs along the interlayer, not along the intralayer. The high diffusion energy barrier induced large polarization when the interlayer Li+ transport became dominant. The energy of the polarization electric field would be instantaneously released like a short electric pulse, which generated a substantial amount of joule heat and created an extremely high temperature, causing the melting of the tungsten tip. We provide another possible fundamental mechanism of thermal failure in graphite-based Li-ion batteries and hope this insightful work would help the safety management of graphite-based lithium-ion batteries.

With increasing global energy demand and stricter environmental protection requirements, energy storage technology has become a research hotspot in the global energy field. New types of energy storage devices continue to emerge owing to the continuous development of cost-effective energy storage technology. Among them, potassium-ion batteries have received widespread attention as a new type of alkali metal ion battery because of their high capacity and low cost and are considered one of the future development directions. However, the research on potassium-ion batteries is still in its infancy, with many challenges to overcome regarding practical applications. A key factor affecting the performance of potassium-ion batteries is the anode material, as it not only affects the manufacturing costs but also directly affects the power density and energy density of the battery. Traditional anode materials for lithium-ion batteries cannot meet the requirements of potassium-ion batteries. Therefore, developing high-performance anode materials suitable for potassium-ion batteries is an important research direction at present. The charge and discharge rate and cycling life of potassium-ion batteries also need further improvements. Currently, the low-rate performance, short cycle life, and unsatisfactory practical capacities limit their practical application and commercialization. However, the future of potassium-ion batteries remains promising. Upon resolving the aforementioned issues, potassium-ion batteries will have diverse application prospects, such as electric vehicles, energy storage stations, and smart grids, providing important support for solving energy problems. Therefore, the research and development of potassium-ion batteries are an important direction in the global energy field. Current research efforts are primarily focused on exploring novel anode materials with exceptional ratability and cyclability. In this regard, we synthesized a new type of anode material based on bismuth telluride (Bi2Te3) and experimentally studied its applicability in potassium-ion batteries. The performance of Bi2Te3 anode for potassium-ion batteries has been limited by its structural instability and slow electrochemical reaction kinetics. In this study, rod-like Bi2Te3 was grown on accordion-like MXene, followed by P-doping to obtain a high-performance P-Bi2Te3/MXene superstructure. This novel anode had abundant Te vacancies and good self-auto adjustable function, providing excellent cycling stability (323.1 mAh·g-1 after 200 cycles at 0.2 A·g-1) and outstanding rate capability (67.1 mAh·g-1 at 20 A·g-1). Kinetic analysis and ex situ characterization indicate that the superstructure exhibits superior pseudocapacitive properties, high electrical conductivity, favorable diffusion capability, and reversible insertion and conversion reaction mechanism.

The sluggish reaction kinetics and poor structure stability of transition metal dichalcogenides (TMDs)-based anodes in potassium-ion batteries (KIBs) usually cause limited rate performance and rapid capacity decay, which seriously impede their application. Herein, we report a vacancy engineering strategy for preparing a class of Te-doped 1T’-ReSe2 anchored onto MXene (Te-ReSe2/MXene) as an advanced anode for KIBs with high performance. By taking advantage of the synergistic effects of the defective Te-ReSe2 arrays with expanded interlayers and the elastic MXene nanosheets with self-autoadjustable function, the Te-ReSe2/MXene superstructure exhibits boosted K+ ion storage performance, in terms of high reversible capacity (361.1 mA h g−1 at 0.1 A g−1 over 200 cycles), excellent rate capability (179.3 mA h g−1 at 20 A g−1), ultra-long cycle life (202.8 mA h g−1 at 5 A g−1 over 2000 cycles), and steady operation in flexible full battery, presenting one of the best performances among the TMDs-based anodes reported thus far. The kinetics analysis and theoretical calculations further indicate that satisfactory pseudocapacitive property, high electronic conductivity and outstanding K+ ion adsorption/diffusion capability corroborate the accelerated reaction kinetics. Especially, structural characterizations clearly elaborate that the Te-ReSe2/MXene undergoes reversible evolutions of an initial insertion process followed by a conversion reaction.

High-concentration electrolytes (HCEs) can effectively enhance interface stability and cycle performance of Li metal batteries (LMBs). However, HCEs suffer from low ionic conductivity, high viscosity, high cost, and high density. Herein, fluorobenzene (FB) diluted localized high-concentration electrolytes (LHCEs) consisting of lithium bis(fluorosulfonyl)imide (LiFSI)/triethyl phosphate (TEP)/FB are developed. 2.3 M LHCE can reserve concentrated Li+-FSI--TEP solvation structures. Diluent FB possesses low density, low viscosity, low cost, low dielectric constant, low LUMO, and a good fluorine-donating property, which can significantly reduce viscosity, improve ionic conductivity, promote the formation of LiF-rich SEI, and enhance interaction of Li+-TEP and Li+-FSI- ion-pairs of the electrolytes. 2.3 M LHCE is a highly safe nonflammable electrolyte. 2.3 M LHCE can effectively inhibit dendrite growth on Li metal anode. 2.3 M LHCE endows LiFePO4 cells with good rate capability (discharge capacity of 112.7 mAh g-1 at 5 C rate) and excellent cycling performance (capacity retention of 95.4% after 1000 cycles). 2.3 M LHCE also shows good compatibility with LiNi0.8Co0.1Mn0.1O2 and exhibits outstanding cycle stability (capacity retention of 86.4% after 500 cycles). Therefore, 2.3 M LHCE is a promising electrolyte for practical applications in LMBs.

Improving the high‐rate performance of spinel lithium titanate (Li 4 Ti 5 O 12 , LTO) is one of the critical requirements to promote its practical application in Li‐ion batteries (LIBs). Herein, the possible Li + ion diffusion routes in LTO are theoretically analyzed and compared by computational investigation. The calculations show that the most feasible diffusion path for Li + ions is along the [110] direction indicated by the lowest energy barrier. Inspired by this prediction, ultrathin [110]‐confined LTO nanoflakes are rationally prepared through a function‐led targeted synthesis. The [110] orientation of the material sufficiently provides preferable transport channels which can promote the anisotropic diffusion of lithium ions within LTO nanoflakes. Furthermore, the ultrathin 2D nanostructure effectively shortens the diffusion length along the [110] direction, facilitating ion transport across the nanoflakes and thus improving the diffusion kinetics. Owing to these unique features, the LIB composed of optimized [110]‐confined LTO exhibits remarkable high rate capability and long‐term cycling stability, with a capacity of 146 mAh g ‐1 at an ultrahigh rate of 100 C and a capacity retention of 88% even after 1500 cycles at 50 C. The as‐prepared [110]‐confined LTO nanoflakes have promising applications and show commercial viability for high‐power facilities.

MXene, an emerging family of 2D transition metal carbides/nitride (MXene) materials, has attracted growing attention since its initial discovery in 2011. Owing to their extraordinary electrical conductivity, high mechanical stability, various functional groups, and large interlayer space, MXene and MXene-based nanomaterials have shown significant energy-storage capability. Firstly, research progress on the preparation strategies and properties of MXene are summarized. Secondly, the current state-of-the-art advances of MXene and MXene-based nanomaterials as advanced electrodes for energy storage devices, including lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, and supercapacitors are reviewed. Finally, the key challenges and perspectives for further enhancing their electrochemical performances are also outlined. This Progress Report offers a reference and scientific inspiration for the design and preparation of high-performance MXene and MXene-based nanomaterials to meet the increasing need for next-generation energy-storage systems.

Potassium-ion batteries (PIBs) are a promising candidate for next-generation electric energy storage applications because of the abundance and low cost of potassium. However, the development of PIBs is limited by sluggish kinetics and huge volume expansion of anodes, leading to poor rate capability and cycling stability. Herein, an advanced superstructure anode, including Te-doped SnS2 nanosheets uniformly anchored on MXene surface (Te-SnS2/MXene), is rationally designed for the first time to boost K+ storage performance. Featuring with strong interface interaction and self-autoadjustable interlayer spacings, the Te-SnS2/MXene can efficiently accelerate electron/ion transfer, accommodate volume expansion, inhibit crack formation, and improve pseudocapacitive contribution during cycling. Thus, the novel Te-SnS2/MXene anode delivers a high reversible capacity (343.2 mAh g(-1) after 50 cycles at 0.2 A g(-1)), outstanding rate capability (186.4 mAh g(-1) at 20 A g(-1)), long cycle stability (165.8 mAh g(-1) after 5000 cycles at 10 A g(-1) with a low electrode swelling rate of only 15.4%), and reliable operation in flexible full battery. The present Te-SnS2/MXene becomes among the best transition metal-based anode materials for PIBs reported to date. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

In article number 2003270, Shengfu Tong, Mingmei Wu and co-workers design an oriented lithium titanate (Li4Ti5O12) anode for high-rate lithium storage. [110]-oriented channels in the structure enable ultrafast lithium ion transport. The lithium-ion battery shows high rate capability and superior cycling stability. This [110]-oriented Li4Ti5O12 material shows promise for application in high-power energy storage facilities.

Silicon is one of the most promising candidates for anode materials for next-generation lithium-ion batteries due to its high theoretical capacity. However, the catastrophic volume change upon lith...

A flame-retardant single-ion conducting polymer electrolyte was constructed by incorporating allylboronic acid pinacol ester into the 3D network to trap the anions, leading to unity lithium-ion transference number and high ionic conductivity.

The fast and reversible potassiation/depotassiation of anode materials remains an elusive yet intriguing goal. Herein, a class of the P‐doping‐induced orthorhombic CoTe2 nanowires with Te vacancy defects supported on MXene (o‐P‐CoTe2/MXene) is designed and prepared, taking advantage of the synergistic effects of the conductive o‐P‐CoTe2 arrays with rich Te vacancy defects and the elastic MXene sheets with self‐autoadjustable function. Consequently, the o‐P‐CoTe2/MXene superstructure exhibits boosted potassium‐storage performance, in terms of high reversible capacity (373.7 mAh g−1 at 0.2 A g−1 after 200 cycles), remarkable rate capability (168.2 mAh g−1 at 20 A g−1), and outstanding long‐term cyclability (0.011% capacity decay per cycle over 2000 cycles at 2 A g−1), representing the best performance in transition‐metal‐dichalcogenides‐based anodes to date. Impressively, the flexible full battery with o‐P‐CoTe2/MXene anode achieves a satisfying energy density of 275 Wh kg−1 and high bending stability. The kinetics analysis and first‐principles calculations reveal superior pseudocapacitive property, high electronic conductivity, and favorable K+ ion adsorption and diffusion capability, corroborating fast K+ ion storage. Especially, ex situ characterizations confirm o‐P‐CoTe2/MXene undergoes reversible evolutions of initially proceeding with the K+ ion insertion, followed by the conversion reaction mechanism.

Layered nickel-rich transition metal oxide has been receiving much attention as high-energy-density cathode materials for rechargeable lithium-ion batteries. However, the severe capacity fading caused by bulk structural degradation of Ni-rich cathodes during lithiation/delithiation obstructs their commercialization. Herein, we modify the LiNi0.92Co0.06Al0.02O2(NCA92) cathode materials by W(6+)cation and BO(3)(3-)polyanion co-doping to improve the structural stability and upgrade the electrochemical reversibility. The co-doped NCA92 materials show remarkably improved cycling stability at 1 C with a capacity retention of 93.4 % after 100 cycles, whereas the pristine cathodes exhibit poor capacity retention of 53.0 % and suffer severe structural deterioration. Further studies reveal that the particle fragmentation resulted from the inherent internal strain and the structural degradation upon cycling can be effectively mitigated by W(6+)cation and BO(3)(3-)polyanion co-doping. Besides, W(6+)and BO(3)(3-)co-doping could enlarge the interlayer spacing of NCA92, thus increasing lithium-ion diffusion coefficient, which is conducive to enhancing the rate capability. The present work demonstrates that cationic-anionic co-doping is an effective strategy to maintain the structural stability of Ni-rich cathode materials, and it promotes the development of stable cathode materials for high energy density lithium-ion batteries.