三维多孔结构和亲锌性梯度协同构筑无枝晶锌电极  

Three-Dimensional Porous Structure and Zincophile Gradient Enabling Dendrite Free Zinc Anode

作　　者：宋瑞 赵铭钦 王帅[1] 卢垚 鲍晓冰 罗巧梅 苟蕾[1] 樊小勇[1] 李东林[1] Song Rui;Zhao Mingqin;Wang Shuai;Lu Yao;Bao Xiaobing;Luo Qiaomei;Gou Lei;Fan Xiaoyong;Li Donglin(School of Material Science and Engineering,Chang’an University,Xi’an 710061,China)

机构地区：[1]长安大学材料科学与工程学院,西安710061

出　　处：《化学学报》2024年第4期426-434,共9页Acta Chimica Sinica

基　　金：国家自然科学基金面上项目(No.22179011);陕西重点研发计划一般工业项目(No.2023-YBGY-445)资助.

摘　　要：锌离子电池具有能量密度高、安全性好、价格低廉等优点,被认为是规模化储能的理想选择之一.然而,其锌负极在电化学循环过程中易产生枝晶、析氢和表面钝化等,造成电池库伦效率低、锌利用率低和循环寿命短等缺陷,限制了其规模化应用.本工作采用电沉积法在自制三维多孔铜内先沉积具有高亲锌性的PbSn合金层,再沉积Zn层,最后通过化学置换,在上层孔表面获得PbSn合金层,其在ZnSO_(4)电解液中形成较低亲锌性的PbSO_(4)层,最终形成由三维多孔内部到外部亲锌性逐渐降低的具有三维亲锌性梯度的锌电极3D Cu@PbSn@Zn@PbSn(3D Cu@PSZPS).三维多孔结构可提高电极比表面积,提供更均匀的电场分布,降低电流密度,提高锌沉积容量,抑制枝晶生长、析氢和钝化;内层孔PbSn合金具有高亲锌性,可诱导锌从内层孔沉积,抑制锌枝晶生长;Pb和Sn具有高析氢过电位,可抑制析氢,同时抑制由于析氢致使电极表面pH值升高而产生的钝化.因此该电极结构可获得优异的电化学性能,在电流密度5 mA•cm^(−2),面积容量1 mAh•cm^(−2)的条件下,可实现锌的稳定沉积/剥离900次以上,首圈成核过电位仅16.4 mV,首圈库伦效率高达99.66%;以此电极组装的对称电池可以稳定循环超过700 h;采用商业MnO_(2)与之匹配得到的MnO_(2)||3D Cu@PSZPS全电池在0.3 A•g^(−1)时具有238.7 mAh•g^(−1)的可逆比容量和300次循环后79.4%的容量保持率,在1.8 A•g^(−1)的电流密度下可稳定循环2000次以上.Zn-ion batteries have been considered as one of the most promising grid storage devices due to their high energy densities,high safety,and low cost.However,the Zn anode suffers dendrite growth,hydrogen evolution and surface passivation,resulting in low coulombic efficiency,low Zn utilization,and poor cyclability.In this work,PbSn alloy is firstly electrodeposited in the self-prepared three-dimensional(3D)porous Cu,then a Zn layer is electrodeposited on it,finally the partial Zn layer on outer pores is replaced by PbSn alloy,which will transform into PbSO_(4) in ZnSO_(4)-based electrolyte,and a Zn electrode with 3D porous structure and zincophile gradient is achieved 3D Cu@PbSn@Zn@PbSn(3D Cu@PSZPS).The 3D porous structure can provide high specific area,small and uniform current distribution,as a result enhance Zn plating capacity,inhibit Zn dendrites growth,hydrogen evolution and passivation.The PbSn alloy layer in inner pores can induce Zn plating from inner to outer pores,inhibit dendrites growth;high hydrogen evolution overpotential feature of Pb and Sn can inhibit hydrogen evolution,and also inhibit the passivation caused by increase of pH value.This modification strategy effectively circumvents the inherent limitations associated with solely relying on a single strategy.Therefore,this electrode demonstrates excellent electrochemical performance.It can stably cycle for more than 900 times at 5 mA•cm^(−2),1 mAh•cm^(−2) with a high first coulombic efficiency of 99.66%,low first nucleation potential of 16.4 mV.The symmetrical cell assembled using this electrode can stably cycle for more than 700 h.The MnO_(2)||3D Cu@PSZPS full cell shows a high reversible specific capacity of 238.7 mAh•g^(−1) at 0.3 A•g^(−1) and a capacity retention of 79.4%over 300 cycles,and can be stably cycling more than 2000 times under the current density of 1.8 A•g^(−1).

关 键 词：水系锌离子电池 负极 协同策略 三维多孔 亲锌性梯度 

分 类 号：TM912[电气工程—电力电子与电力传动] O646[理学—物理化学]