摘要
真空冷喷涂是一种基于室温及真空条件下超细陶瓷粉末粒子的撞击破碎实现涂层沉积的方法。目前,真空冷喷涂技术已经在微电子器件,金属防护以及新能源领域展现了良好的应用前景。本研究将目光转向锂离子电池,基于真空冷喷涂技术,在氧化铝基体上制备了锂离子电池LiNi_(0.33)Co_(0.33)Mn_(0.33)O_2(NMC)三元材料正极涂层,使用扫面电子显微镜(SEM)观察了NMC涂层的表面及截面微观形貌,使用X射线衍射(XRD)对涂层的相结构进行了测试,使用3D激光显微镜表征了涂层的表面粗糙度,系统研究了载气流量、喷涂距离、喷涂次数等沉积条件对NMC涂层微观形貌及粒子沉积行为的影响。结果表明,在真空冷喷涂NMC涂层中可以观察到明显颗粒破碎沉积现象,涂层结构致密。NMC粉末颗粒沉积方式受气流量、喷涂距离、喷涂次数等沉积条件的影响,载气流量的提高会提高粒子撞击速度,从而提高涂层沉积速率,但过高的气流量会导致粒子发生冲蚀,在涂层表面留下凹坑,致使涂层粗糙度增大。喷涂距离过大会导致NMC颗粒撞击速度减小,粒子破碎不充分,涂层呈现出类似团聚粉末堆积的疏松结构。喷涂次数影响涂层厚度,在合适的沉积参数条件下,可以通过调整喷涂次数实现涂层厚度的线性调控。
Vacuum cold spray is a coating deposition method that is based on the impact and crush of ultrafine ceramic powder particles under room temperature and vacuum condition.Currently,vacuum cold spray has shown good application prospects in the fields of microelectronic devices,metal protection and new energy sources.In this study,LiNi_(0.33)Co_(0.33)Mn_(0.33)O_2(NMC) coating that is used for the cathode of lithium-ion battery was deposited on alumina substrate by the vacuum cold spray method.The surface and cross-section morphology of the NMC coating were characterized by scanning electron microscopy(SEM).The phase structure of the coating was characterized by X-ray diffraction(XRD).The surface roughness of the coatings was characterized by 3 D laser microscope.The effects of deposition conditions such as carrier gas flow rate,spray distance and spray passes on the micro-morphology and particle deposition behavior of the NMC coatings were studied.The results show that particles crush is determined in the vacuum cold spray NMC coatings.The cross-section microstructure of the NMC coatings is dense.The particles deposition behavior is affected by the deposition conditions such as the gas flow rate,spray distance,spray passes.The increase of particle impact speed is increased by the carrier gas flow rate,which results in the increase of the deposition rate of NMC coating.However,excessive gas flow rate leads to particle erosion,which leaves pits on the surface of NMC coatingand results inthe increase of coating roughness.Excessive spray distance results in low impact velocity of NMC particles and inadequate particle fragmentation.The coating is porous at high spray distanceand the structure is similar to agglomerated NMC powder.The coating thickness increases with the increase of spray passes.Under appropriate deposition parameters,the thickness of the coating can be linearly varied by adjusting the spray passes.
引文
[1]Akedo J.Room Temperature Impact Consolidation(RTIC)of Fine Ceramic Powder by Aerosol Deposition Method and Applications to Microdevices[J].Journal of Thermal Spray Technology,2008,17(2):181-198.
[2]Akedo J.Aerosol Deposition of Ceramic Thick Films at Room Temperature:Densification Mechanism of Ceramic Layers[J].Journal of the American Ceramic Society,2006,89(6):6.
[3]Chun D M,Ahn S H.Deposition mechanism of dry sprayed ceramic particles at room temperature using a nano-particle deposition system[J].ActaMaterialia,2011,59(7):2693-2703.
[4]Akedo J,Lebedev M.Microstructure and Electrical Properties of Lead ZirconateTitanate(Pb(Zr52/Ti48)O3)Thick Films Deposited by Aerosol Deposition Method[J].Japanese Journal of Applied Physics,1999,38(Part 1,No.9B):5397.
[5]李京龙,孙福,张赋升,等.气浮沉积技术[J].机械科学与技术,2006,25(2):177-180.
[6]Hanft D,J?rgExner,Schubert M,et al.An Overview of the Aerosol Deposition Method:Process Fundamentals and New Trends in Materials Applications[J].Journal of Ceramic Science and Technology,2015,6(3):147-182.
[7]Yang G J,Li C J,Liao K X,et al.Influence of gas flow during vacuum cold spraying of nano-porous TiO2 film by using strengthened nanostructured powder on performance of dye-sensitized solar cell[J].Thin Solid Films,2011,519(15):4709-4713.
[8]Wang L S,Li C X,Ma K,et al.La0.8Sr0.2Ga0.8Mg0.2O3Electrolytes Prepared by Vacuum Cold Spray Under Heated Gas for Improved Performance of SOFCs[J].Ceramics International,2018,44(12):13773-13781.
[9]Akedo J,Lebedev M.Effects of annealing and poling conditions on piezoelectric properties of Pb(Zr0.52,Ti0.48)O3 thick films formed by aerosol deposition method[J].Journal of Crystal Growth,2002,235(1):415-420.
[10]孙玉城.镍钴锰酸锂三元正极材料的研究与应用[J].无机盐工业,2014,46(1):1.
[11]Xie J,Imanishi N,Zhang T,et al.An amorphous LiCo1/3Mn1/3Ni1/3O2,thin film deposited on NASICON-type electrolyte for all-solid-state Li-ion batteries[J].Journal of Power Sources,2010,195(17):5780-5783.
[12]Baskaran R,Kuwata N,Kamishima O,et al.Structural and electrochemical studies on thin film LiNi0.8Co0.2O2,by PLDfor micro battery[J].Solid State Ionics,2009,180(6):636-643.
[13]Kim I,Nam T H,Kim K W,et al.LiNi0.4Co0.3Mn0.3O2thin film electrode by aerosol deposition[J].Nanoscale Research Letters,2012,7(1):1-6.
[14]Stoltenhoff T,Kreye H,Richter H J.An analysis of the cold spray process and its coatings[J].Journal of Thermal Spray Technology,2002,11(4):542-550.
[15]Johnson S D,Schwer D,Park D-S,et al.Deposition efficiency of barium hexaferrite by aerosol deposition[J].Surface and Coatings Technology,2017,332:542-549.
[16]王丽爽,周恒福,李成新,等.真空冷喷涂致密Al2O3陶瓷涂层微观结构的研究[J].热喷涂技术,2017(3):36-45.