Implementing high-performance silicon(Si)anode in actual processing and application is highly desirable for next-generation,high-energy Li-ion batteries.However,high content of inactive matrix(including conductive age...Implementing high-performance silicon(Si)anode in actual processing and application is highly desirable for next-generation,high-energy Li-ion batteries.However,high content of inactive matrix(including conductive agent and binder)is often indispensable in order to ensure local conductivity and suppress pulverization tendency of Si particles,which thus cause great capacity loss based on the mass of whole electrode.Here,we designed an accordion-structured,high-performance electrode with high Si content up to 95%.Si nanoparticles were well anchored into the interlayer spacings of accordion-like graphene arrays,and free-standing electrode was prepared via a simple filtration process without any binder.Conductive accordion framework ensures strong confinement effect of Si nanoparticles and also provides direct,non-tortuous channels for fast electrochemical reaction kinetics.As a consequence,the accordion Si electrodes exhibit ultrahigh,electrode-based capacities up to 3149 mAh g^(-1)(under Si content of 91%),as well as long-term stability.Also,the accordion electrode can bear extreme condition of over-lithiation and maintains stable in full-cell test.This design provides a significant stride in high Si content toward realistic,high-performance electrodes.展开更多
The anode-free design is a promising strategy to increase the energy density of aqueous Zn metal batteries(AZMBs).However,the scarcity of Zn-rich cathodes and the rapid loss of limited Zn greatly hinder their commerci...The anode-free design is a promising strategy to increase the energy density of aqueous Zn metal batteries(AZMBs).However,the scarcity of Zn-rich cathodes and the rapid loss of limited Zn greatly hinder their commercial applications.To address these issues,a novel anode-free Zniodine battery(AFZIB)was designed via a simple,low-cost and scalable approach.Iodine plays bifunctional roles in improving the AFZIB overall performance:enabling high-performance Zn-rich cathode and modulating Zn deposition behavior.On the cathode side,the ZnI_(2) serves as Zn-rich cathode material.The graphene/polyvinyl pyrrolidone heterostructure was employed as an efficient host for ZnI_(2) to enhance electron conductivity and suppress the shuttle effect of iodine species.On the anode side,trace I_(3)^(−) additive in the electrolyte creates surface reconstruction on the commercial Cu foil.The in situ formed zincophilic Cu nanocluster allows ultralow-overpotential and uniform Zn deposition and superior reversibility(average coulombic efficiency>99.91% over 7,000 cycles).Based on such a configuration,AFZIB exhibits significantly increased energy density(162 Wh kg^(−1)) and durable cycle stability(63.8% capacity retention after 200 cycles)under practical application conditions.Considering the low cost and simple preparation methods of the electrode materials,this work paves the way for the practical application of AZMBs.展开更多
Lithium-and manganese-rich(LMR)layered cathode materials hold the great promise in designing the next-generation high energy density lithium ion batteries.However,due to the severe surface phase transformation and str...Lithium-and manganese-rich(LMR)layered cathode materials hold the great promise in designing the next-generation high energy density lithium ion batteries.However,due to the severe surface phase transformation and structure collapse,stabilizing LMR to suppress capacity fade has been a critical challenge.Here,a bifunctional strategy that integrates the advantages of surface modification and structural design is proposed to address the above issues.A model compound Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)(MNC)with semi-hollow microsphere structure is synthesized,of which the surface is modified by surface-treated layer and graphene/car-bon nanotube dual layers.The unique structure design enabled high tap density(2.1 g cm^(−3))and bidirectional ion diffusion pathways.The dual surface coatings covalent bonded with MNC via C-O-M linkage greatly improves charge transfer efficiency and mitigates electrode degradation.Owing to the synergistic effect,the obtained MNC cathode is highly conformal with durable structure integrity,exhibiting high volumetric energy density(2234 Wh L^(−1))and predominant capacitive behavior.The assembled full cell,with nanograph-ite as the anode,reveals an energy density of 526.5 Wh kg^(−1),good rate performance(70.3%retention at 20 C)and long cycle life(1000 cycles).The strategy presented in this work may shed light on designing other high-performance energy devices.展开更多
使用低成本、高安全性的水系电解液使二次锌金属电池(AZMBs)成为大规模储能系统是最有前途的选择.然而,锌金属负极在水系电解液中热力学稳定性较差,严重阻碍了AZMBs的实际应用.在此,我们通过在锌表面涂覆氟化石墨并利用氟化石墨和锌之...使用低成本、高安全性的水系电解液使二次锌金属电池(AZMBs)成为大规模储能系统是最有前途的选择.然而,锌金属负极在水系电解液中热力学稳定性较差,严重阻碍了AZMBs的实际应用.在此,我们通过在锌表面涂覆氟化石墨并利用氟化石墨和锌之间原位的界面反应开发了一种富氟的杂化人工固体电解质界面来解决上述问题.疏水的氟化石墨可以有效地限制电解液和电极之间的接触,从而显著提高锌负极的抗腐蚀能力.同时,由氟化石墨和锌原位反应生成的ZnF_(2)共同组成的富氟杂化界面可以促进Zn2+的脱溶剂化作用,并均匀化锌离子通量,从而有效地抑制了副反应发生和枝晶生长.因此,在苛刻的测试条件下(10 mA cm^(−2),1 mA h cm^(−2)和30 mA cm^(−2),10 mA h cm^(−2)),对称电池可以分别稳定地循环1400和200小时以上,远远超过了裸锌的性能.此外,使用载量为6 mg cm^(−2)的MnO_(2)正极组装的Zn/MnO_(2)全电池在1 A g^(−1)的条件下经过2000次循环,仍能保持80%以上的容量.本文提出的这种构建富氟杂化ASEI的方法可以为设计高性能AZMBs提供一种有效的潜在策略.展开更多
基金supported by Shaanxi Yanchang Petroleum Co.,Ltd.(18529)Yiwu Research Institute of Fudan University(21557)+1 种基金the National Science Foundation of China(22075048)the Shanghai International Collaboration Research Project(19520713900).
文摘Implementing high-performance silicon(Si)anode in actual processing and application is highly desirable for next-generation,high-energy Li-ion batteries.However,high content of inactive matrix(including conductive agent and binder)is often indispensable in order to ensure local conductivity and suppress pulverization tendency of Si particles,which thus cause great capacity loss based on the mass of whole electrode.Here,we designed an accordion-structured,high-performance electrode with high Si content up to 95%.Si nanoparticles were well anchored into the interlayer spacings of accordion-like graphene arrays,and free-standing electrode was prepared via a simple filtration process without any binder.Conductive accordion framework ensures strong confinement effect of Si nanoparticles and also provides direct,non-tortuous channels for fast electrochemical reaction kinetics.As a consequence,the accordion Si electrodes exhibit ultrahigh,electrode-based capacities up to 3149 mAh g^(-1)(under Si content of 91%),as well as long-term stability.Also,the accordion electrode can bear extreme condition of over-lithiation and maintains stable in full-cell test.This design provides a significant stride in high Si content toward realistic,high-performance electrodes.
基金This work was financially supported by Shaanxi Yanchang Petroleum CO.,Ltd(18529)Yiwu Research Institute of Fudan University(21557),the National Science Foundation of China(22075048)the Shanghai International Collaboration Research Project(19520713900).
文摘The anode-free design is a promising strategy to increase the energy density of aqueous Zn metal batteries(AZMBs).However,the scarcity of Zn-rich cathodes and the rapid loss of limited Zn greatly hinder their commercial applications.To address these issues,a novel anode-free Zniodine battery(AFZIB)was designed via a simple,low-cost and scalable approach.Iodine plays bifunctional roles in improving the AFZIB overall performance:enabling high-performance Zn-rich cathode and modulating Zn deposition behavior.On the cathode side,the ZnI_(2) serves as Zn-rich cathode material.The graphene/polyvinyl pyrrolidone heterostructure was employed as an efficient host for ZnI_(2) to enhance electron conductivity and suppress the shuttle effect of iodine species.On the anode side,trace I_(3)^(−) additive in the electrolyte creates surface reconstruction on the commercial Cu foil.The in situ formed zincophilic Cu nanocluster allows ultralow-overpotential and uniform Zn deposition and superior reversibility(average coulombic efficiency>99.91% over 7,000 cycles).Based on such a configuration,AFZIB exhibits significantly increased energy density(162 Wh kg^(−1)) and durable cycle stability(63.8% capacity retention after 200 cycles)under practical application conditions.Considering the low cost and simple preparation methods of the electrode materials,this work paves the way for the practical application of AZMBs.
基金The authors greatly appreciate the financial support from the National Science Foundation of China(22075048,51173027,21875141)Beijing National Laboratory for Condensed Matter Physics,Shanghai International Collaboration Research Project(19520713900).
文摘Lithium-and manganese-rich(LMR)layered cathode materials hold the great promise in designing the next-generation high energy density lithium ion batteries.However,due to the severe surface phase transformation and structure collapse,stabilizing LMR to suppress capacity fade has been a critical challenge.Here,a bifunctional strategy that integrates the advantages of surface modification and structural design is proposed to address the above issues.A model compound Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)(MNC)with semi-hollow microsphere structure is synthesized,of which the surface is modified by surface-treated layer and graphene/car-bon nanotube dual layers.The unique structure design enabled high tap density(2.1 g cm^(−3))and bidirectional ion diffusion pathways.The dual surface coatings covalent bonded with MNC via C-O-M linkage greatly improves charge transfer efficiency and mitigates electrode degradation.Owing to the synergistic effect,the obtained MNC cathode is highly conformal with durable structure integrity,exhibiting high volumetric energy density(2234 Wh L^(−1))and predominant capacitive behavior.The assembled full cell,with nanograph-ite as the anode,reveals an energy density of 526.5 Wh kg^(−1),good rate performance(70.3%retention at 20 C)and long cycle life(1000 cycles).The strategy presented in this work may shed light on designing other high-performance energy devices.
基金financially supported by the National Natural Science Foundation of China(22075048 and 52201201)Shaanxi Yanchang Petroleum Co.,Ltd.(18529)+2 种基金Yiwu Research Institute of Fudan University(20-1-06)Shanghai International Collaboration Research Project(19520713900)the State Key Lab of Advanced Metals and Materials(2022Z-11).
文摘使用低成本、高安全性的水系电解液使二次锌金属电池(AZMBs)成为大规模储能系统是最有前途的选择.然而,锌金属负极在水系电解液中热力学稳定性较差,严重阻碍了AZMBs的实际应用.在此,我们通过在锌表面涂覆氟化石墨并利用氟化石墨和锌之间原位的界面反应开发了一种富氟的杂化人工固体电解质界面来解决上述问题.疏水的氟化石墨可以有效地限制电解液和电极之间的接触,从而显著提高锌负极的抗腐蚀能力.同时,由氟化石墨和锌原位反应生成的ZnF_(2)共同组成的富氟杂化界面可以促进Zn2+的脱溶剂化作用,并均匀化锌离子通量,从而有效地抑制了副反应发生和枝晶生长.因此,在苛刻的测试条件下(10 mA cm^(−2),1 mA h cm^(−2)和30 mA cm^(−2),10 mA h cm^(−2)),对称电池可以分别稳定地循环1400和200小时以上,远远超过了裸锌的性能.此外,使用载量为6 mg cm^(−2)的MnO_(2)正极组装的Zn/MnO_(2)全电池在1 A g^(−1)的条件下经过2000次循环,仍能保持80%以上的容量.本文提出的这种构建富氟杂化ASEI的方法可以为设计高性能AZMBs提供一种有效的潜在策略.