Understanding dynamic storage mechanisms and tuning electrode interfaces is vital for designing highperformance potassium-ion battery(KIB)anodes.Despite their high capacities,transition metal telluride(TMTe)anodes oft...Understanding dynamic storage mechanisms and tuning electrode interfaces is vital for designing highperformance potassium-ion battery(KIB)anodes.Despite their high capacities,transition metal telluride(TMTe)anodes often suffer from sluggish K+diffusion and severe volume expansion during cycling,highlighting the need for structurally optimized and interface-engineered architectures.While such strategies have been proven to be effective in lithium-and sodium-ion batteries,their use in TMTe-based KIB anodes remains largely unexplored.In this study,we firstly introduce a heterointerface-engineered three-dimensional microsphere composed of ZnTe nanoparticles and uniformly encapsulated by MXene(denoted MX/ZnTe@NC).Importantly,a built-in electric field(BIEF)is induced at the MXeneZnTe interface due to their work function.This interfacial field modulates the local electronic structure and significantly accelerates K^(+)adsorption and diffusion kinetics,especially under high current densities.First-principles simulations and spectroscopic analyses confirm that the BIEF significantly increases the K~+adsorption strength and lowers the energy barriers for ion transport.Electrochemical analyses reveal that the MX/ZnTe@NC anode delivers a high reversible capacity of 283 mAh g^(-1)after 1000 cycles at 0.5 A g^(-1),with nearly 100%Coulombic efficiency.Even at 10 A g^(-1),the anode retains a capacity of 83 mAh g^(-1),indicating excellent rate performance.Additionally,in-situ and ex-situ characterizations reveal a highly reversible ZnTe conversion mechanism involving dynamic intermediate phases.This study provides mechanistic insight into the structural and chemical evolution during cycling and highlights the synergistic role of interfacial field engineering and three-dimensional heterostructure design in advancing MXene-based KIB anodes.展开更多
Li4Ti50i2 (LTO) has attracted considerable attention in lithium-ion battery (LIB) applications because of its favorable characteristics as an anode material. Despite its promise, the widespread use of LTO is still lim...Li4Ti50i2 (LTO) has attracted considerable attention in lithium-ion battery (LIB) applications because of its favorable characteristics as an anode material. Despite its promise, the widespread use of LTO is still limited primarily due to its intrinsically poor electric and ionic con ductivities and high surface reactivity. To address these issues, we desig ned polyg onal nano architectures composed of various Li-Ti oxide crystal polymorphs by a facile synthesis route. Depending on the pH condition, this synthesis approach yields multi-polymorphed Li-Ti oxides where the interior is dominantly composed of a Li-rich phase and the exterior is a Li-deficient (or Li-free) phase. As one of these variations, a polygonal LTO-rutile TiO2 structure is formed. The rutile TiO2 on the surface of this LTO composite significantly improves the kinetics of Li^+ insertion/extraction because the channel along the o-axis in TQ2 provides a Li^+ highway due to the significantly low energy barrier for Li^+ diffusion. Moreover, the presenee of rutile TiO2, which is less reactive with a carbonate-based electrolyte, ensures Iong-term stability by suppress)ng the undesirable interfacial reaction on LTO.展开更多
基金supported by the Materials/Parts Technology Development Program(No.RS-2024-00456324)funded by the Ministry of Trade,Industry and Energy(MOTIE,Korea)the 2025 Research Fund of Hongik Universitysupported by the MSIT,Korea,under the ITRC support program(IITP-RS-2024-00436248)supervised by the IITP。
文摘Understanding dynamic storage mechanisms and tuning electrode interfaces is vital for designing highperformance potassium-ion battery(KIB)anodes.Despite their high capacities,transition metal telluride(TMTe)anodes often suffer from sluggish K+diffusion and severe volume expansion during cycling,highlighting the need for structurally optimized and interface-engineered architectures.While such strategies have been proven to be effective in lithium-and sodium-ion batteries,their use in TMTe-based KIB anodes remains largely unexplored.In this study,we firstly introduce a heterointerface-engineered three-dimensional microsphere composed of ZnTe nanoparticles and uniformly encapsulated by MXene(denoted MX/ZnTe@NC).Importantly,a built-in electric field(BIEF)is induced at the MXeneZnTe interface due to their work function.This interfacial field modulates the local electronic structure and significantly accelerates K^(+)adsorption and diffusion kinetics,especially under high current densities.First-principles simulations and spectroscopic analyses confirm that the BIEF significantly increases the K~+adsorption strength and lowers the energy barriers for ion transport.Electrochemical analyses reveal that the MX/ZnTe@NC anode delivers a high reversible capacity of 283 mAh g^(-1)after 1000 cycles at 0.5 A g^(-1),with nearly 100%Coulombic efficiency.Even at 10 A g^(-1),the anode retains a capacity of 83 mAh g^(-1),indicating excellent rate performance.Additionally,in-situ and ex-situ characterizations reveal a highly reversible ZnTe conversion mechanism involving dynamic intermediate phases.This study provides mechanistic insight into the structural and chemical evolution during cycling and highlights the synergistic role of interfacial field engineering and three-dimensional heterostructure design in advancing MXene-based KIB anodes.
文摘Li4Ti50i2 (LTO) has attracted considerable attention in lithium-ion battery (LIB) applications because of its favorable characteristics as an anode material. Despite its promise, the widespread use of LTO is still limited primarily due to its intrinsically poor electric and ionic con ductivities and high surface reactivity. To address these issues, we desig ned polyg onal nano architectures composed of various Li-Ti oxide crystal polymorphs by a facile synthesis route. Depending on the pH condition, this synthesis approach yields multi-polymorphed Li-Ti oxides where the interior is dominantly composed of a Li-rich phase and the exterior is a Li-deficient (or Li-free) phase. As one of these variations, a polygonal LTO-rutile TiO2 structure is formed. The rutile TiO2 on the surface of this LTO composite significantly improves the kinetics of Li^+ insertion/extraction because the channel along the o-axis in TQ2 provides a Li^+ highway due to the significantly low energy barrier for Li^+ diffusion. Moreover, the presenee of rutile TiO2, which is less reactive with a carbonate-based electrolyte, ensures Iong-term stability by suppress)ng the undesirable interfacial reaction on LTO.
