Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)Ni...Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.展开更多
HfO_(2)基薄膜由于其与互补金属氧化物半导体(complementary metal oxide-semiconductor,CMOS)工艺的兼容性以及在微小尺寸下保持铁电性的能力,在高密度逻辑器件和非易失性存储器等新型器件中具有广阔的应用前景。在HfO_(2)基薄膜中,亚...HfO_(2)基薄膜由于其与互补金属氧化物半导体(complementary metal oxide-semiconductor,CMOS)工艺的兼容性以及在微小尺寸下保持铁电性的能力,在高密度逻辑器件和非易失性存储器等新型器件中具有广阔的应用前景。在HfO_(2)基薄膜中,亚稳铁电相(正交相)的稳定调控及铁电性的优化对于实现高性能铁电器件至关重要。系统研究了La_(1-x)Sr_(x) MnO_(3)(L(S)MO)底电极中Sr掺杂比例对Hf_(0.5)Zr_(0.5) O_(2)(HZO)铁电薄膜正交相和铁电极化的影响,通过X射线衍射(X-Ray Diffraction,XRD)和铁电极化分析发现,底电极中Sr掺杂浓度显著影响HZO薄膜的铁电性,当Sr掺杂比例为30%时(La_(0.7)Sr_(0.3)MnO_(3)),其上的HZO薄膜具有最强的铁电正交相衍射峰强度,展现出最高的极化(25μC/cm^(2)),两者呈正相关,进一步证实了正交相HZO的铁电性。研究为外延HZO薄膜的底电极选择提供了重要实验依据,对HfO_(2)基铁电器件的设计与优化具有指导意义。展开更多
基金supported by the Significant Science and Technology Project in Xiamen(Future Industry Field)(Grant No.3502Z20231057).
文摘Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.
