Dual-modification of manganese oxide by heterostructure and cation pre-intercalation for high-rate and stable zinc-ion storage

Zinc-ion batteries(ZIBs)possess great advantages in terms of high safety and low cost,and are regarded as promising alternatives to lithium-ion batteries(LIBs).However,limited by the electrochemical kinetics and structural stability of the typical cathode materials,it is still difficult to simultaneously achieve high rates and high cycling stability for ZIBs.Herein,we present a manganese oxide(Sn_(x)Mn O_(2)/Sn O_(2))material that is dual-modified by Sn O_(2)/Mn O_(2)heterostructures and pre-intercalated Sn;cations as the cathode material for ZIBs.Such modification provides sufficient hetero-interfaces and expanded interlayer spacing in the material,which greatly facilitates the insertion/extraction of Zn^(2+).Meanwhile,the“structural pillars”of Sn^(4+) cations and the“pinning effect”of SnO_(2)also structurally stabilizes the Mn O_(2)species during the repeated Zn^(2+) insertion/extraction,leading to ultra-high cycling stability.Due to these merits,the Sn_(x)MnO_(2)/SnO_(2)cathode exhibits a high reversible capacity of 316.1 m Ah g^(-1) at 0.3 A g^(-1),superior rate capability of 179.4 m Ah g^(-1) at 2 A g^(-1),and 92.4%capacity retention after 2000 cycles.Consequently,this work would provide a promising yet efficient strategy by combining heterostructures and cations preintercalation to obtain high-performance cathodes for ZIBs.

Synergism of preintercalated manganese ions and lattice water in vanadium oxide cathodes for high-capacity and long-life Zn-ion batteries

Aqueous Zn-ion batteries(AZIBs)are recognized as a promising energy storage system with intrinsic safety and low cost,but its applications still rely on the design of high-capacity and stable-cycling cathode materials.In this work,we present an intercalation mechanism-based cathode materials for AZIB,i.e.the vanadium oxide with pre-intercalated manganese ions and lattice water(noted as MVOH).The synergistic effect between Mn^(2+)and lattice H_(2)O not only expands the interlayer spacing,but also significantly enhances the structural stability.Systematic in-situ and ex-situ characterizations clarify the Zn^(2+)/H^(+)co–(de)intercalation mechanism of MVOH in aqueous electrolyte.The demonstrated remarkable structure stability,excellent kinetic behaviors and ion-storage mechanism together enable the MVOH to demonstrate satisfactory specific capacity of 450 mA h g^(−1)at 0.2 A g^(−1),excellent rate performance of 288.8 mA h g^(−1)at 10 A g^(−1)and long cycle life over 20,000 cycles at 5 A g^(−1).This work provides a practical cathode material,and contributes to the understanding of the ion-intercalation mechanism and structural evolution of the vanadium-based cathode for AZIBs.

Revealing the role of calcium ion intercalation of hydrated vanadium oxides for aqueous zinc-ion batteries

Exploring suitable high-capacity V_(2)O_(5)-based cathode materials is essential for the rapid advancement of aqueous zinc ion batteries(ZIBs).However,the typical problem of slow Zn^(2+)diffusion kinetics has severely limited the feasibility of such materials.In this work,unique hydrated vanadates(CaVO,BaVO)were obtained by intercalation of Ca^(2+)or Ba^(2+)into hydrated vanadium pentoxide.In the CaVO//Zn and BaVO//Zn batteries systems,the former delivered up to a 489.8 mAh g^(-1)discharge specific capacity at 0.1 A g^(-1).Moreover,the remarkable energy density of 370.07 Wh kg^(-1)and favorable cycling stability yard outperform BaVO,pure V_(2)O_(5),and many reported cathodes of similar ionic intercalation compounds.In addition,pseudocapacitance analysis,galvanostatic intermittent titration(GITT)tests,and Trasatti analysis revealed the high capacitance contribution and Zn^(2+)diffusion coefficient of CaVO,while an in-depth investigation based on EIS elucidated the reasons for the better electrochemical performance of CaVO.Notably,ex-situ XRD,XPS,and TEM tests further demonstrated the Zn^(2+)insertion/extraction and Zn-storage mechanism that occurred during the cycle in the CaVO//Zn battery system.This work provides new insights into the intercalation of similar divalent cations in vanadium oxides and offers new solutions for designing cathodes for high-capacity aqueous ZIBs.

Weakly Polarized Organic Cation-Modified Hydrated Vanadium Oxides for High-Energy Efficiency Aqueous Zinc-Ion Batteries

Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic characteristics,and high theoretical capacities.However,challenges such as vanadium dissolution,sluggish Zn^(2+)diffusion kinetics,and low operating voltage still hinder their direct application.In this study,we present a novel vanadium oxide([C_(6)H_(6)N(CH_(3))_(3)]_(1.08)V_(8)O_(20)·0.06H_(2)O,TMPA-VOH),developed by pre-inserting trimethylphenylammonium(TMPA+)cations into VOH.The incorporation of weakly polarized organic cations capitalizes on both ionic pre-intercalation and molecular pre-intercalation effects,resulting in a phase and morphology transition,an expansion of the interlayer distance,extrusion of weakly bonded interlayer water,and a substantial increase in V^(4+)content.These modifications synergistically reduce the electrostatic interactions between Zn^(2+)and the V-O lattice,enhancing structural stability and reaction kinetics during cycling.As a result,TMPA-VOH achieves an elevated open circuit voltage and operation voltage,exhibits a large specific capacity(451 mAh g^(-1)at 0.1 A g^(-1))coupled with high energy efficiency(89%),the significantly-reduced battery polarization,and outstanding rate capability and cycling stability.The concept introduced in this study holds great promise for the development of high-performance oxide-based energy storage materials.

Boosting the kinetics of PF_(6)^(-) into graphitic layers for the optimal cathode of dual-ion batteries:The rehearsal of pre-intercalating Li^(+)

Large anions exhibit slow diffusion kinetics in graphite cathode of dual-ion batteries(DIBs);particularly at high current density,it suffers severely from the largely-reduced interlayer utilization of graphite cathode,which as a bottleneck limits the fast charge application of DIBs.To maximize interlayer utilization and achieve faster anion diffusion kinetics,a fast and uncrowded anion transport channel must be established.Herein,Li^(+)was pre-intercalated into the graphite paper(GP)cathode to increase the interlayer spacing,and then hosted for the PF_(6)^(-)anion storage.Combined with theoretical calculation,it shows that the local interlayer spacing enlargement and the residual Li^(+)reduce the anion intercalation energy and diffusion barrier,leading to better rate stability.The obtained GP with Li^(+)pre-intercalation(GP-Li)electrode exhibits a discharge capacity of 23.1 m Ah g^(-1) at a high current of 1300 m A g^(-1).This work provides a facile method to efficiently improve the interlayer utilization of graphite cathode at large currents.

Weaker Interactions in Zn^(2+)and Organic Ion-pre-intercalated Vanadium Oxide toward Highly Reversible Zinc-ion Batteries

Driven by safety issues,environmental concerns,and high costs,rechargeable aqueous zinc-ion batteries(ZIBs)have received increasing attention in recent years owing to their unique advantages.However,the sluggish kinetics of divalent charge Zn^(2+)in the cathode materials caused by the strong electrostatic interaction and their unsatisfactory cycle life hinder the development of ZIBs.Herein,organic cations and Zn^(2+)ions co-pre-inserted vanadium oxide([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O are reported as the cathode for ultra-stable aqueous ZIBs,in which the weaker electrostatic interactions between Zn^(2+)and organic ion-pinned vanadium oxide can induce the high reversibility of Zn^(2+)insertion and extraction,thereby improving the cycle life.It is demonstrated that([N(CH_(3))_(4)]_(0.77),Zn_(0.23))V_(8)O_(20)·3.8H_(2)O cathodes deliver a discharge capacity of 181 mA h g^(-1)at8 A g^(-1)and ultra-long life span(99.5%capacity retention after 2000 cycles).A reversible Zn^(2+)/H^(+)ions(de)intercalation storage process and pseudocapacitive charge storage are characterized.The weaker interactions between organic ion and Zn^(2+)open a novel avenue for the design of highly reversible cathode materials with long-term cycling stability.

Methylene blue intercalated vanadium oxide with synergistic energy storage mechanism for highly efficient aqueous zinc ion batteries

With the rise of aqueous multivalent rechargeable batteries,inorganic-organic hybrid cathodes have attracted more and more attention due to the complement of each other’s advantages.Herein,a strategy of designing hybrid cathode is adopted for high efficient aqueous zinc-ion batteries(AZIBs).Methylene blue(MB)intercalated vanadium oxide(HVO-MB)was synthesized through sol-gel and ion exchange method.Compared with other organic-inorganic intercalation cathode,not only can the MB intercalation enlarge the HVO interlayer spacing to improve ion mobility,but also provide coordination reactions with the Zn^(2+)to enhance the intrinsic electrochemical reaction kinetics of the hybrid electrode.As a key component for the cathode of AZIBs,HVO-MB contributes a specific capacity of 418 mA h g^(-1) at 0.1 A g^(-1),high rate capability(243 mA h g^(-1) at 5 A g^(-1))and extraordinary stability(88%of capacity retention after 2000cycles at a high current density of 5 A g^(-1))in 3 M Zn(CF_(3)SO_(3))_(2) aqueous electrolyte.The electrochemical kinetics reveals HVO-MB characterized with large pseudocapacitance charge storage behavior due to the fast ion migration provided by the coordination reaction and expanded interlayer distance.Furthermore,a mixed energy storage mechanism involving Zn^(2+)insertion and coordination reaction is confirmed by various ex-situ characterization.Thus,this work opens up a new path for constructing the high performance cathode of AZIBs through organic-inorganic hybridization.

Oxygen vacancies and N-doping in organic–inorganic pre-intercalated vanadium oxide for high-performance aqueous zinc-ion batteries

Pre-intercalation of metal ions into vanadium oxide is an effective strategy for optimizing the performance of rechargeable zinc-ion battery(ZIB)cathodes.However,the battery long-lifespan achievement and high-capacity retention remain a challenge.Increasing the electronic conductivity while simultaneously prompting the cathode diffusion kinetics can improve ZIB electrochemical performance.Herein,N-doped vanadium oxide(N-(Zn,en)VO)via defect engineering is reported as cathode for aqueous ZIBs.Positron annihilation and electron paramagnetic resonance clearly indicate oxygen vacancies in the material.Density functional theory(DFT)calculations show that N-doping and oxygen vacancies concurrently increase the electronic conductivity and accelerate the diffusion kinetics of zinc ions.Moreover,the presence of oxygen vacancies substantially increases the storage sites of zinc ions.Therefore,N-(Zn,en)VO exhibits excellent electrochemical performance,including a peak capacity of 420.5 mA h g^(-1)at 0.05 A g^(-1),a high power density of more than 10000 W kg^(-1)at 65.3 Wh kg^(-1),and a long cycle life at 5 A g^(-1)(4500 cycles without capacity decay).The methodology adopted in our study can be applied to other cathodic materials to improve their performance and extend their practical applications.

Cr^(3+)pre-intercalated hydrated vanadium oxide as an excellent performance cathode for aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries(ZIBs)are regarded as the next promising large scale energy storage systems owing to their low cost,high safety and environmental friendliness.Vanadium-based materials are one of the most important cathodes of ZIBs due to their high abundance and multielectron transfer of various oxidations of vanadium.Nevertheless,the strong electrostatic interaction between Zn^(2+)and cathodes,intrinsic poor electronic conductivity and solubility of vanadium-based cathodes in electrolytes bring about inferior electrochemical performance.In this work,we introduce aliovalent Cr^(3+)into the interlayer of hydrated vanadium oxide(Cr-VOH)as pillar to significantly increase the structural stability and electrochemical reversibility.The pre-intercalation of Cr^(3+)also provides an enhanced electronic conductivity and fast Zn^(2+)diffusion dynamics,enabling superior Zn2+storage performance of the Cr-VOH cathode.As a result,the Cr-VOH cathode exhibits a high reversible discharge capacity of~380 mAh g^(−1)at 50 mA g^(−1),excellent rate capacity of 166 mAh g^(−1)at 8 A g^(−1)and prolonged cycling stability over 500 cycles.Furthermore,it displays a high energy density of 273.6 W h kg^(−1)at 0.05 A g^(−1)and the power density of 4960 W kg^(−1)at 8 A g^(−1),contributing to the practical application potential of aqueous ZIBs.

Multi-ion intercalated Ti_(3)C_(2)T_(x)MXene and the mutual modulation within interlayer

Intercalation of ions between the adjacent MXene layers can change the interlayer environment and influence the electrochemical ion storage capacity.In order to understand the effect of multi-ions confined by the MXene layers on the performance of electrochemical energy storage,Co^(2+),Mn^(2+)and Ni^(2+)intercalated into Ti_(3)C_(2)T_(x)MXene which already pre-intercalated Al3+are obtained by spontaneous static action.Based on the monitor of(002)crystal orientation,intercalated multi-ions can regulate and control the interlayer environment of MXenes via stress,which induces lattice shrinkage occurring in the c axis.Limited by ion storage mechanism-performance,the multi-ion occupies the interspace of MXene and affects the electrochemical performance.This work would offer guidance to understand the relationship among the multi-ion and MXene by two-dimensional(2D)layered materials.

Organic interlayer engineering of TiS_(2) for enhanced aqueous Zn ions storage

Aqueous rechargeable zinc-ion batteries(ARZIBs)have a bright future for energy storage due to their high energy density and safety.However,for traditional ARZIBs,cathode materials always suffer from the limited space for large-sized zinc ions storage and transport,leading to low Coulombic efficiency and inferior cycling performance.To build a reliable host with large tunnel,1-butyl-1-methylpyrrolidinium ion(PY14^(+))pre-intercalated TiS_(2)(PY14^(+)-TiS_(2))is designed as an alternative intercalation-type electrode.As the insertion organic guest widens the interlayer space of TiS_(2)and buffers the lattice stress generated during the electrochemical cycles,the structural reversibility,cycling stability and kinetics properties of PY14^(+)-TiS_(2) are enhanced greatly.A specific capacity of 130.9 mAh g^(−1) with 84.3%capacity retention over 500 cycles can be achieved at 0.1 A g^(−1).Therefore,this study paves the way for enhancing the aqueous Zn ions storage capability by organic interlayer engineering.

Silver vanadate(Ag_(0.33)V_(2)O_(5))nanorods from Ag intercalated vanadium pentoxide for superior cathode of aqueous zinc-ion batteries

Silver vanadate(Ag_(0.33)V_(2)O_(5))nanorods were successfully synthesized by the pre-intercalation of Ag+into the interlayer of V_(2)O_(5)through a sol-gel method,which presented a favorable electrochemical performance of high capacity,rate capacity,and cycle stability.Specific ally,Ag_(0.33)V_(2)O_(5)electrode presented a high capacity of about 311 mAh·g^(-1)at the current density of0.1 A·g^(-1).It also delivered long-term cycling stability(144 mAh·g^(-1)after 500 cycles at 2 A·g^(-1)).The reasons for the superior electrochemical performance were the preintercalation Ag^+extended interlayer distance,and the introduction of elemental silver improved conductivity during charge/discharge.Additionally,the Zn^(2+)storage mechanism was revealed by various characteristic measurements.The prepared Ag_(0.33)V_(2)O_(5)nanorods from the sol-gel method were demonstrated as a promising cathode material for aqueous Zn^(2+)batteries.

NaV6O15:A promising cathode material for insertion/extraction of Mg^2+with excellent cycling performance

The rechargeable magnesium batteries(RMBs)are getting more and more attention because of their high-energy density,high-security and low-cost.Nevertheless,the high charge density of Mg^2+makes the diffusion of Mg2+in the conventional cathodes very slow,resulting in a lack of appropriate electrode materials for RMBs.In this work,we enlarge the layer spacing of V2Os by introducing Na^2+in the crystal structure to promote the diffusion kinetics of Mg^2+.The NaVeO15(NVO)synthesized by a facile method is studied as a cathode material for RMBs with the anhydrous pure Mg^2+electrolyte.As a result,the NVO not only exhibits high discharge capacity(119.2 mAh:g^-1 after 100 cycles at the current density of 20 mA:g^-1)and working voltage(above 1.6 V vs.Mg^2+/Mg),but also expresses good rate capability.Besides,the eX-situ characterizations results reveal that the Mg^2+storage mechanism in NVO is based on the intercalation and deintercalation.The density functional theory(DFT)calculation results further indicate that Mg^2+tends to occupy the semi-occupied sites of Na^+in the NVO.Moreover,the galvanostatic intermittent titration technique(GITT)demonstrates that NVO electrode has the fast diffusion kinetics of Mg^2+during discharge process ranging from 7.55×10^-13 to2.41×10^-11 cm^2·s^-1.Our work proves that the NVO is a potential cathode material for RMBs.

Calcium ion pinned vanadium oxide cathode for high-capacity and long-life aqueous rechargeable zinc-ion batteries

Rechargeable aqueous zinc ion batteries (ZIBs),with the easy operation,cost effectiveness,and high safety,are emerging candidates for high-energy wearable/portable energy storage systems.Unfortunately,the unsatisfactory energy density and undesired long-term cycling performance of the cathode hinder the development of ZIBs.Here,we report the chemical preintercalation of a small amount of calcium ions into V2O5 as the cathode material.The cathode of Ca0.04V2O5·1.74H2O (CVO)was demonstrated to have a high specific capacity of 400 mA h g^-1at the current density of 0.05 A g^-1and 187 mA h g^-1at 10 A g^-1,along with impressive capacity retention (100%capacity retention at 10 A g^-1 for 3,000 cycles).Meanwhile,the CVO//Zn battery exhibits a high energy density of 308 Wh kg^-1and a power density of 467 W kg^-1at 0.5 A g^-1.The superior performance originates from the pinning effect of the calcium ions and the lubricating effect of the structural water.The energy storage mechanism of the CVO cathode was also investigated in detail.The new phase (Zn3(OH)2V2O7·2H2O) generated upon cycling participates in the electrochemical reaction and thus contributes to the excellent electrochemical performance.The small amount of Ca^2+ pre-inserted into the interlayer of V2O5 sheds light on constructing cathodes with high energy density for ZIBs.

原位电化学改性的预插层钒青铜水系锌离子电池正极材料

钒青铜是一种极具潜力的水系锌离子电池正极材料.然而,传统的单离子预插层V_(4)O_(9)材料由于自身结构的限制和储锌过程中发生不可逆的相变使其储锌能力接近上限.本文采用原位阴极氧化法将准层状材料Ca V_(4)O_(9)在特定的电解液中将双离子(Ca^(2+), Zn^(2+))引入δ-V_(4)O_(9)晶体骨架中,形成超薄钒青铜材料Ca^(2+)Zn^(2+)V_(4)O_(9)·n H_(2)O.该材料表现出超高的能量密度(366 W h kg^(-1))和功率密度(6627 W kg^(-1)),并在大电流10 A g^(-1)下循环3000圈后可逆比容量仍高达205 m A h g^(-1).通过多种原位/非原位表征,系统地揭示了材料与Ca^(2+)电解液添加剂的协同作用,使结构、电化学可逆性和反应动力学得到有效提升,并凸显了电解液调控对转化反应过程的重要性.经过理论计算,阐明了双离子预嵌入衍生的“支柱”增强效应、电荷屏蔽效应和调控电子结构对增强电荷储存性能的作用.