Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategie...Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.展开更多
Single oxygen diffusion event,the most favorable rate-limiting process of epitaxial Cu_(2)O oxide-island layerby-layer growth kinetics,may lead to oxygen defects due to thermomechanical coupling.However,the formation ...Single oxygen diffusion event,the most favorable rate-limiting process of epitaxial Cu_(2)O oxide-island layerby-layer growth kinetics,may lead to oxygen defects due to thermomechanical coupling.However,the formation rules of oxygen defects remain unclear,preventing the realization of controllable oxygen defects on oxide-island surfaces.Here,we utilize the first-principles method to investigate the formation rules of intrinsic oxygen defects in the surface layers of prototypical metal-oxide(Cu_(2)O)surfaces under thermomechanical coupling effects.We establish the thermodynamic phase diagram for oxygen-defect-modulated Cu_(2)O surfaces,enabling the prediction of the growth of oxide islands during Cu oxidation,which aligns closely with in-situ environmental transmission electron microscopy(ETEM)experiment observations.By exploring the strain-modulated phase diagrams,we propose a potential strategy for controlling the type and concentration of oxygen defects on oxide-island surfaces.Our findings provide an effective approach to theoretically understanding the oxidation process of metal surfaces,thus enabling the computational design of high-performance corrosion-resistant surfaces.展开更多
基金supported by the National Natural Science Foundation of China(52222407).
文摘Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.
基金supported by the National Natural Science Foundation of China(U2230402,T2325004).
文摘Single oxygen diffusion event,the most favorable rate-limiting process of epitaxial Cu_(2)O oxide-island layerby-layer growth kinetics,may lead to oxygen defects due to thermomechanical coupling.However,the formation rules of oxygen defects remain unclear,preventing the realization of controllable oxygen defects on oxide-island surfaces.Here,we utilize the first-principles method to investigate the formation rules of intrinsic oxygen defects in the surface layers of prototypical metal-oxide(Cu_(2)O)surfaces under thermomechanical coupling effects.We establish the thermodynamic phase diagram for oxygen-defect-modulated Cu_(2)O surfaces,enabling the prediction of the growth of oxide islands during Cu oxidation,which aligns closely with in-situ environmental transmission electron microscopy(ETEM)experiment observations.By exploring the strain-modulated phase diagrams,we propose a potential strategy for controlling the type and concentration of oxygen defects on oxide-island surfaces.Our findings provide an effective approach to theoretically understanding the oxidation process of metal surfaces,thus enabling the computational design of high-performance corrosion-resistant surfaces.
