一步烧结制备锂镧钛氧直孔陶瓷及其固态电池性能研究

One-Step Sintering Preparation of Lithium Lanthanum Titanium Oxide Straight-Hole Ceramics and Solid-State Battery Performance

锂镧钛氧(LLTO)陶瓷电解质因具有高的离子电导率和热稳定性,成为制备固态电池的理想材料,然而传统的电解质制备方法存在界面接触差、步骤烦琐、高温烧结过程中锂损耗大等问题。针对这些问题,开发了一种用于合成具有直孔结构的LLTO陶瓷电解质的一步烧结法,深入研究了一步烧结制备的LLTO陶瓷电解质的微观形貌和电化学性能。结果表明,该方法能够一步合成和烧结具有直孔结构的LLTO陶瓷,从而有效规避了多次烧结过程中的锂损失,增强了LLTO陶瓷的致密化程度,降低了晶界阻抗。通过一步烧结法制备的LLTO陶瓷电解质在室温时表现出2.31×10^(-4) S/cm的高电导率。此外,使用所制备的直孔LLTO陶瓷电解质组装的Li/Li对称电池具有良好的锂离子沉积剥离性能,在0.1 mA/cm^(2)的电流密度下循环超过350 h。使用该电解质组装的全固态锂电池在0.2 C倍率下进行200次循环后,容量保持率为94%,证明了一步烧结所制备的直孔LLTO陶瓷具有优异的稳定性。

Lithium lanthanum titanium oxide(LLTO) ceramic electrolyte possesses high ion conductivity and thermal stability,rendering it an ideal candidate for solid-state batteries.However,conventional methods of electrolyte preparation suffer from drawbacks such as poor interface contact,cumbersome procedures,and significant lithium loss during high-temperature sintering.To address these issues,a one-step sintering method to synthesize LLTO ceramic electrolytes with a straight-hole structure was developed.The micromorphology and electrochemical properties of one-step sintering prepared LLTO ceramic electrolytes were thoroughly investigated.The results reveal that this method enables the synthesis and sintering of LLTO ceramics with straight-hole structure in one step,thereby efficiently circumventing lithium loss during multiple sintering processes,enhancing the densification of LLTO ceramics,and reducing grain boundary resistance.Notably,LLTO ceramic electrolytes synthesized via one-step sintering method exhibit a high conductivity of 2.31×10^(-4) S/cm at room temperature.Moreover,Li/Li symmetric batteries assembled using this electrolytes demonstrate excellent Li~+ deposition and stripping performance,which can be stable cycling for over 350 h at a current density of 0.1 mA/cm^(2).Furthermore,the all-solid-state lithium battery assembled with this electrolytes maintains a capacity retention rate of 94% after 200 cycles at a rate of 0.2 C,demonstrating the exceptional stability of straight-hole LLTO ceramics prepared via one-step sintering.