06-Hydrogen Storage materials

*,Click to edit Master title style,Click to edit Master text styles,Second Level,Third Level,Fourth Level,Fifth Level,Tel: 0571- 8795 1152,Email:,lxchen,zju.,edu,.,cn,Laboratory of Hydrogen Storage Materials,Institute of Metallic Materials,Zhejiang,University,Hydrogen Storage Materials,Dr. Li-xin Chen,1,Vanadium Based Hydrogen Storage Alloys,Lecture V,2,I,.,Basic characteristic of V-group elements,Position in the,B,group of element periodic table,3,2.1 Reaction,. V-H systems,Pure V and hydrogen can form two hydrides as VH and VH,2,.,C,VH,= 1.9 wt.% H,2,C,VH2,= 3.81 wt.% H,2,4,2.2 Features,. V-H systems,1) high capacity (3.81 wt.% H,2,);,2) solid solution type hydride with b.c.c. structure;,3) two pressure plateaus of,P-C-T,curve;,5,high diffusivity of H atom in V ( like Pd ) ;,. V-H systems,Inactivation;,Oxide film on the surface of alloys, need heating at 300550,.,Expensive.,Study in Japan: V,2,O,5, pure V.,6,3.1 Multi-component alloying,1),V,1-,x,M,x,(M = Ti, Cr, Fe,Zr,Hf, Al .),A.J.,Maeland,et al,.,Such as:,V,0.9,Ti,0.1, V,0.99,Ag,0.01, V,0.99,Hf,0.01, V,0.99,In,0.01,. V-based alloys for gaseous application,Hydriding,rate ;,Capacity .,7,Dehydriding,P-C-T curves at 313 K of V-1mol% M alloys,. V-based alloys for gaseous application,8,2) (,V,1-,x,Ti,x,)M,y,(M = Al,Si,Zr, Cr, Fe, Co, Ni; x=0.10.2; y=0.010.1),Kagawa,et al,.,Such as:,(V,0.9,Ti,0.1,),0.98,Zr,0.02,(V,0.9,Ti,0.1,),0.95,Cr,0.05,(V,0.9,Ti,0.1,),0.95,Fe,0.05,H/M = 1.85 ;,good cycling life,.,.,V-based alloys for gaseous application,9,3),V-Ti-Fe system,Miyamura,et al,.,Multi-phase structures include:,V-Ti,TiFe, C14,FeV, TiFe,2,can absorb/,desorb,hydrogen,.,V-based alloys for gaseous application,10,4),V-Ti-Cr system,M. Okada, E.,Akiba, L.X. Chen,et al,.,As Ti/Cr = 0.75, the alloys have high capacity ;,.,V-based alloys for gaseous application,Relation between the hydrogen storage capacity and the Ti/Cr ratio,11,.,V-based alloys for gaseous application,As V content,activation,C,abs, and,C,des,reaches the highest at 50 at.% ;,Low hydrogen,desorption,efficiency:, maximum,C,abs,= 2.73.6 wt.%;,maximum,C,des,2.4 wt.%;,Commonly alloying with,Zr,Mn,and Fe etc.,12,5),V-Ti-Cr-M,(M =,Mn, Fe,),system,M. Okada, S.W.,Cho, L.X. Chen,et al,.,+,Mn,:,hysteresis, and effective,C,des,first,than,but activation and absorbing capacity,;,+,Fe :,homosphere, cycling life, cell volume,P,eq, but absorbing capacity,.,.,V-based alloys for gaseous application,13,5),V-Ti-Cr-,Zr,system,S.W.,Cho, L.X. Chen,et al,.,Hysteresis,;,.,V-based alloys for gaseous application,Activation, but plateau slope,due to the formation of ZrCr,2,secondary phase;,Absorbing capacity,due to ZrCr,2,phase;,As Ti/Cr,0.70, the formation of ZrCr,2,is restrained ;,Adding a small quantity of,Zr, such as annealed V,57,Ti,16,Zr,5,Cr,22,can acquire the highest C,abs,= 3.55 wt.% and,C,des,= 2.14 wt.%,14,.,V-based alloys for gaseous application,15,6,),V +,x,wt%,TiFe,0.85,Mn,0.15,(x=50,60,70),C.P. Chen,et al,.,As,x,= 60, activation behavior , good P-C-T characteristic and over-all properties;,.,V-based alloys for gaseous application,16,1) Heat treatment,3.2,The effects of preparation,technics,high temperature annealing and rapid cooling (water cooling),effective desorbing capacity,.,V-based alloys for gaseous application,such as:,heated at 1573K,1min and water cooling,f or V,35,Ti,25,Cr,40,;,heated at 1473K,8hrs and water cooling,for V,57,Ti,16,Zr,5,Cr,22,.,17,2) Mechanical ball-milling,such as:, V or V-based alloys + (Ti, Ni, LaNi,5, etc) ,prepared by ball-milling,activation,;,.,V-based alloys for gaseous application,kinetics,.,18,. V-based alloys for electrochemical application,V or V-based solid solution (V-Ti etc.) cannot charge and discharge due to their,unelectric,-catalysis activation .,1995,IMRA,(,材料开发研究所,),and ONRI,(,大阪工业技术研究所,),found that V,3,Ti alloy added with Ni can form double-phase structure alloys as V,3,TiNi,x,(x=0.250.75), they have charging/discharging ability.,19,This type alloys are composed of a main phase of a V-based solid solution phase with b.c.c. structure and a secondary,TiNi,-based phase with a three dimensional net-work.,. V-based alloys for electrochemical application,Micrographs of V,3,TiNi,0,.,56,composed of a main V-based solid solution phase (dark gray) and a secondary,TiNi,-based phase (bright gray).,20,. V-based alloys for electrochemical application,The schematic illustration for electrode reaction mechanism of V-based solid solution type alloys.,The main phase works as a hydrogen absorption phase;,The secondary phase work as a micro-current collector and a catalyst, so improve charging/discharging ability and electrode kinetics.,21,M.,Tsukahara,and T. Sakai,et al,. reported,V,3,TiNi,0.56,C,max,= 420,mAh,/g,C.,Iwakura,et al,. reported,V,2.1,TiNi,0.3,C,max,= 540,mAh,/g,. V-based alloys for electrochemical application,22,4.1 V-based ternary electrode alloys,1),V,3,TiNi,x,(x=0, 0.25, 0.5, 0.56, 0.75), M.,Tsukahara,and T. Sakai,et al,.,As x,0.25, the alloys are composed of a V-rich (Ti,V) main phase and a,TiNi,-based secondary phase with b.c.c. structure;,. V-based alloys for electrochemical application,As x,0.5, the secondary phase formed a three dimensional net-work, and enhanced electrode kinetics of the alloys.,23,As,x,=0.56, the alloy has a maximum discharge capacity of 420mAh/g at 25mA/g;,As,x, the secondary phase, so the utilization efficiency of electrode; but the main phase (hydrogen storage phase), so the hydrogen storage capacity ;,The HRD and cycling life of V,3,TiNi,0.56,are poor.,. V-based alloys for electrochemical application,24,Discharge capacities of V,3,TiNi,x,(x=00.75) alloys at 293K,(The dashed line shows the discharge capacity calculated from P-C-T curves),. V-based alloys for electrochemical application,25,Cyling,life of V,3,TiNi,0.56,alloy at 293 K,( charged at 100mA/g and discharged at 50mA/g),. V-based alloys for electrochemical application,26,2),Annealed V,3,TiNi,0.56,(973K1473K24h),M.,Tsukahara,et al,.,As annealing temperature,T,a,1273K, a Ti,2,Ni third-phase occurs, and as,T,a, Ti,2,N phase ;,As ,T,a,1173K, the three dimensional net-work of the secondary phase is destroyed and changes to pellet shape; Ti,2,Ni phase forms a strip shape; discharge capacity and cycling life ;,As Ta1173K and ,T,a, mol fraction and cell volume of main phase , and V content in the secondary phase , so capacity and cycling life .,. V-based alloys for electrochemical application,27,Cyling,life of as-cast and annealed V,3,TiNi,0.56,alloys,( charged at 100mA/g and discharged at 50mA/g),. V-based alloys for electrochemical application,28,3),V,2.1,TiNi,0.3,alloy,C.,Iwakura,et al,.,As they studied V,1.4-,x,TiNi,x,(0,x,1) alloys, there was a highest discharge capacity of 430mAh/g at 25mA/g for V,0.9,TiNi,0.5,alloy;,V,0.9,TiNi,0.5,alloy was composed of a V,2.1,TiNi,0.3,main phase and a V,0.2,TiNi,0.8,secondary phase and a Ti,2,Ni third-phase;,When V,2.1,TiNi,0.3,and V,0.2,TiNi,0.8,were prepared independently, V,2.1,TiNi,0.3,has a highest discharge capacity of 540mAh/g at 25mA/g, and its theoretical capacity calculated from P-C-T curve reaches 1055mAh/g;,. V-based alloys for electrochemical application,29,Cycling life of V,2.1,TiNi,0.3, V,0.9,TiNi,0.5,and V,0.2,TiNi,0.8,alloys,(charged at 100mA/g,dischaged,at 50mA/g),. V-based alloys for electrochemical application,30,V,2.1,TiNi,0.3,alloy was composed of a V,2.6,TiNi,0.2,main phase and a V,0.2,TiNi,0.9,secondary phase and a Ti,2,Ni third-phase;,A appropriate ratio of the main phase over the secondary phase is very important for high discharge capacity;,The discharge capacity of V,2.1,TiNi,0.3,is still higher than that of other alloys .,. V-based alloys for electrochemical application,31,Cycling life of V,2.1,TiNi,0.3, V,2.6,TiNi,0.2,and V,3.2,TiNi,0.16,alloys,(charged at 100mA/g,dischaged,at 50mA/g),. V-based alloys for electrochemical application,32,4),V,2.1,TiNi,x,(x=0.1, 0.3, 0.5, 0.7, 0.9),alloy,R.,Guo, L.X. Chen,et al,.,All alloys have a main V-based solid solution phase;,The secondary phase is noticeably dispersed along the grain boundaries of the main phase especially with higher nickel contents;,As x,0.5, the secondary phase starts to encompass the main phase completely, forming a three-dimensional network;,. V-based alloys for electrochemical application,33,SEM graphs of the V,2.1,TiNi,x,(x = 0.1 0.9) alloys,(a) x=0.1; (b) x=0.3; (c) x=0.5; (d) x=0.7; (e) x=0.9,. V-based alloys for electrochemical application,34,V,2.1,TiNi,0.5,alloy with a good combination of the main phase and the secondary phase has the best overall electrochemical performance:,C,max,= 392.5,mAh,/g at 25mA/g ;,372.4,mAh,/g at 50,mA,/g ;,R,30,= 70.60% after 30 cycles.,Cycling life for V,2.1,TiNi,x,alloys,(charged at 100,mA,/g and discharged at 50,mA,/g),. V-based alloys for electrochemical application,35,V,2.1,TiNi,0.3,? or,V,2.1,TiNi,0.5,?,V,2.1,TiNi,x,(x=0.2, 0.3, 0.4, 0.5, 0.6),alloy,F.B. Dai, L.X. Chen,et al,.,V,2.1,TiNi,0.4,alloy shows the highest discharge capacity:,C,max,= 457,mAh,/g at 25mA/g;,363,mAh,/g at 50,mA,/g;,R,30,= 40.5% after 30 cycles.,. V-based alloys for electrochemical application,36,4.2,Multi-component alloying,. V-based alloys for electrochemical application,1),V,3,TiNi,0.56,M,x,(M=,Hf,Zr,Nb, Ta, Al,Si,Mn, Fe, Co,etc,.;,x,=0.046, 0.24),All alloys are composed of a main V-based solid solution phase and a secondary phase;,The alloys with,Zr,(x=0.24) or,Hf,have a C14 Laves secondary phase, the secondary phase of other alloys are still,TiNi,based phase;,37,Among the alloys studied, the,Hf,-contained alloys, such as V,3,TiNi,0.56,Hf,0.046,and V,3,TiNi,0.56,Hf,0.24, have good discharge capacities and HRD, and poor cycling life;,The relationship of discharge capacity and current density for some alloys,. V-based alloys for electrochemical application,38,Nb, Ta, Pd, Mo and,Mn,elements with high solid solubility in V distribute mostly in the V-based main phase;,Al, Fe, Co, Cu,Si,Ge,Zr,and,Hf,elements with low solid solubility in V distribute mostly in the secondary phase;,Nb,and Ta can improve the cycling stability due to their anti-corrosion for the main phase;,Co can enhance the stability of the secondary phase structure, also improve the cycling stability.,. V-based alloys for electrochemical application,39,Maximum discharge capacity and cycling capacity after 50 cycles for V,3,TiNi,0.56,M,x,(x = 0.046, 0.24) alloys added various elements,. V-based alloys for electrochemical application,40,2),V,3,TiNi,0.56,Hf,0.24,M,x,(M=Co,Mn,; x= 00.45),ZJU,As Co content , cycling life ,but,C,max,and HRD ;,Cycle life of V,3,TiNi,0.56,Hf,0.24,Co,x,(x=00.45) alloys,(charged at 100,mA,/g and discharged at 50,mA,/g),. V-based alloys for electrochemical application,41,As ,Mn,content,0.15, cycling life and HRD,but,C,max,;,HRD for V,3,TiNi,0.56,Hf,0.24,Mn,x,(x=00.45) alloys,. V-based alloys for electrochemical application,42,3) V,3,TiNi,0.56,Hf,0.24,Mn,0.15,Cr,x,(x= 00.3),ZJU,As Cr content , cycling life , but,C,max,and HRD ;,V,3,TiNi,0.56,Hf,0.24,Mn,0.15,Cr,0.1,has a good overall properties:,N,a,= 3 cycles,C,max,= 406,mAh,/g,HRD,400/50,= 44.7%,R,30,= 27.1% after 30 cycles,. V-based alloys for electrochemical application,43,4),V,3,TiNb,0.047,Ta,0.047,(Ni,0.56,Co,0.14,),w,(w=0.81.2) alloys,As ,w,cycling life, but,C,dis,;,As,w,= 0.8 or 1.0,good overall properties.,. V-based alloys for electrochemical application,44,5),V,2.1,TiNi,0.5,Hf,x,(x=00.25) alloys,R.,Guo, L.X. Chen,et al,.,As x0.05, the alloys changes the secondary phase from the b.c.c.,TiNi,-based phase to a C14 Laves phase with a three-dimensional network;,The amount of the C14 Laves phase increases with increasing,Hf,content;,V,2.1,TiNi,0.5,Hf,0.05,has a discharge capacity of 444,mAh,/g (discharged at 25,mA,/g), exceeding that of the V,2.1,TiNi,0.5,alloy;,. V-based alloys for electrochemical application,45,X-ray diffraction patterns of V,2.1,TiNi,0.5,Hf,x,alloys,HRD for the V,2.1,TiNi,0.5,Hf,x,alloys,. V-based alloys for electrochemical application,46,4.3 Surface treatment for V-based electrode alloys modified by ball-milling,(,V,2,.,1,TiNi,0,.,3,-,MgNi,),milling in an argon atmosphere;,. V-based alloys for electrochemical application,(,V,2,.,1,TiNi,0,.,3,-Raney Ni),milling in,Ar,atmosphere;,(,V,2,.,1,TiNi,0,.,3,-Raney Ni ),milling in,Ar,atmosphere and in the absence of 0.01M NaH,2,PO,2,solution as a reducing agent.,47,. V-based alloys for electrochemical application,48,. V-based alloys for electrochemical application,49,The difficulties of a task for V-based,HSAs,High thermodynamic,stabilibty,of VH for gas-solid reaction,High degradation rate in electrolyte for electrochemical application,50,Thank you!,The End,51,