摘要
为了改进单金属硫化物循环性能较差,不满足大电流充放电的缺点,选用Fe、Co、Ni、Cu、Sn金属离子,通过共沉淀法和高温煅烧硫化成功制备了一种混合金属硫化物Ni S/Cu_(2)(Fe, Co, Ni)SnS_(4)/碳纳米管复合材料。在充放电过程中,多重金属离子还原成金属单质,促进了离子和电子的传输,抑制了电池极化。Fe、Co、Ni、Cu、Sn金属可以作为活性催化中心以及导电位点增强电池稳定性和倍率性能。NiS和Cu_(2)(Fe,Co,Ni)SnS_(4)之间的异质界面形成了一个内置电场,促进了电化学反应动力学。此外,碳纳米管的引入作为材料间的桥梁,提供了电子传输路径,维持了材料的结构稳定性。对所制备的材料进行储钠性能研究,在5 A·g^(–1)的电流密度下循环1000圈后,放电比容量为626 mA·h·g^(–1),并且在20 A·g^(–1)超大电流密度下循环8000圈之后,还具有399 mA·h·g^(–1)的放电比容量。Ni S/Cu_(2)(Fe, Co, Ni)SnS_(4)/CNT混合金属硫化物负极在大电流密度下展现了优异的电化学性能,解决了金属硫化物导电性差的缺点,为混合金属硫化物负极材料的研究和改性提供了新的视角和思路。
Introduction It is critical for large-scale energy storage to develop sodium-ion batteries(SIBs)due to their cost-effectiveness and abundant sodium resources.However,some challenges like sluggish kinetics from large Na^(+)radii and poor structural stability of electrode materials hinder their practical application.Transition metal sulfides(TMS)like SnS,NiS,and FeS exhibit high theoretical capacities,but suffer from some intrinsic drawbacks(i.e.,low conductivity and severe volume expansion during cycling).To address these limitations,this study was to propose a novel strategy,i.e.,designing a mixed-metal sulfide composite of(NiS/Cu_(2)(Fe,Co,Ni)SnS_(4)/CNT)with heterointerfaces and multi-metal synergy.The integration of Fe,Co,Ni,Cu,and Sn could enhance electronic/ionic transport,mitigate volume changes,and leverage catalytic effects of transition metals.Carbon nanotube(CNT)were introduced to further improve conductivity and structural integrity.This mixed-metal sulfide composite exhibited the excellent performance at a ultra-high current density.Methods The composite was synthesized via a co-precipitation method and a subsequent high-temperature sulfidation.For NiS/Cu_(2)(Fe,Co,Ni)SnS_(4)/CNT,stoichiometric amounts of FeSO_(4),CoSO_(4),NiSO_(4),CuSO_(4),and SnSO_(4) were dissolved and co-precipitated with NaOH.The CNT slurry was ultrasonically dispersed and incorporated into the precursor.After sulfidation with thioacetamide in N2 at 500℃,the final product was obtained.NiS/CNT(control sample)followed the similar process using only NiSO_(4). The crystallinity, morphology, and elemental states of the samples were characterized by X-ray diffraction (XRD), scanningelectron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). To evaluate theirkinetics, rate capability and cycling stability, CR2032 half-cells assembled with Na metal counter electrodes were tested by cyclicvoltammetry (CV), constant-current charge/discharge test, galvanostatic intermittent titration (GITT) and electrochemical impedancespectroscopy (EIS), respectively.Results and discussion The results show that the complex consists of Cu_(2)(Fe,Co,Ni)SnS_(4) and NiS biphasic phases, and theheterogeneous interfaces exist, which are confirmed by high-resolution transmission electron microscopy (HRTEM). The built-inelectric field at the heterogeneous interface accelerates the charge transfer, and the multimetal synergy (Fe/Co/Ni/Cu/Sn) providesabundant catalytic sites and reduces the Na^(+) diffusion barrier (i.e., 32% reduction in the diffusion barrier according todensity-functional theory calculations). The three-dimensional conductive network constructed by the CNTs inhibits the volumeexpansion efficiently (i.e., the thickness of the electrodes increases by only 37.9% after cycling, which is significantly lower than thatof the NiS/CNT). For the electrochemical performance, NiS/Cu_(2)(Fe, Co, Ni)SnS_(4)/CNT exhibits an excellent high ratecharge/discharge performance and a long cycle stability, and still maintains a discharge specific capacity of 626 mA·h·g^(–1) after 1000cycles at a current density of 5 A·g^(–1), and 399 mA·h·g^(–1) after 8000 cycles at an ultra-high current density of 20 A·g^(–1).Capacitive-dominated storage and enhanced Na^(+) diffusivity outperform monometallic NiS/CNT. The TEM images and CV indicate areversible phase transition between sulfide and Na2S, thus validating the reaction mechanism.Conclusions The built-in electric field formed by the heterogeneous interface and the synergistic effect of polymetallic cationscould enhance the ion and charge transfer rate, and the reduction of polymetallic ions to metal monomers facilitated the ion andelectron transport during the charging and discharging process, effectively suppressing the polysulfide shuttling phenomenon, thusdecreasing the polarization of the battery. The introduction of carbon nanotubes provided electron transport paths, which furtherenhanced the structural stability of the material. This study could have a great potential of mixed metal sulfides for application inanode materials for sodium-ion batteries.
作者
杨林
黄思鸣
马竟雄
冯元龙
代文静
周颖宁
秦秋石
李阳光
王明珊
YANG Lin;HUANG Siming;MA Jingxiong;FENG Yuanlong;DAI Wenjing;ZHOU Yingning;QIN Qinshi;LI Yangguang;WANG Mingshan(School of New Energy and Materials,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu 610500,China)
出处
《硅酸盐学报》
北大核心
2025年第7期2001-2012,共12页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金面上项目(52072322)
四川省科技计划项目重点研发项目(2025YFHZ0172,2024ZDZX0033)。
关键词
混合金属硫化物
负极
钠离子电池
超大电流密度
mixed metal sulfides
anode
sodium-ion battery
ultra-high current density
