摘要
The uneven deposition of lithium(Li) on current collectors causes serious dendrite growth and volume expansion. Commercial foamed copper(Cu) current collectors are unsuitable for Li anodes because of their large volume and mass and lithiophobic nature. Herein, a three-dimensional(3 D) copper@tin(Cu@Sn) nanocone current collector with small volume, light weight, and lithiophilic nature was prepared by a simple electrodeposition method. The synergy of the nanoconical structure and lithiophilic Sn promotes the even deposition of Li and effectively inhibits the formation of Li dendrites. The resultant half batteries exhibit high Coulombic efficiency of 97.6% after 100 cycles at 1 mA cm^(-2), and the symmetrical Li battery demonstrates a prolonged lifespan of over 600 h at 1 mA cm^(-2). The full battery based on organic liquid electrolyte with LiFePO_(4) also exhibits a long lifespan of 550 cycles with high capacity retention of 95.1% at 1 C.Moreover, 3 D Cu@Sn nanocone-based solid-state batteries exhibit excellent electrochemical performance and show no decay after 500 cycles at 1 C. Our work provides a strategy for fabricating 3 D current collectors for high-energy-density Li metal batteries.
锂在集流体上的不均匀沉积将导致严重的枝晶生长和体积膨胀等问题,传统的商业化泡沫铜集流体由于具有较大的体积和质量会降低电池的能量密度.本文通过简单的电沉积方法制备了体积小、重量轻,具有亲锂性的3D Cu@Sn纳米锥集流体.从成核与沉积的角度出发,纳米锥结构与亲锂的锡纳米颗粒的协同作用促进了锂的均匀沉积,可有效地抑制锂枝晶的生长.组装的半电池在1 mA cm^(-2)下经过100次循环后,库仑效率高达97.6%,锂对称电池在1 mA cm^(-2)下可以稳定循环600 h.将沉积金属锂后的Cu@Sn/Li复合负极与LiFePO_(4)组装的液态全电池在1 C倍率下, 550个循环之后,容量保持率为95.1%.此外, Cu@Sn纳米锥集流体在固态电池Li/Cu@Sn|PVDF–HFP–5 wt%Si O_(2)|LFP中也表现出优异的电化学性能,在1 C倍率下, 500个循环之后,放电容量未发生衰减.
基金
supported by the National Natural Science Foundation of China (51771094 and 21835004)
the National Key R&D Program of China (2016YFB0901500)
the Ministry of Education of China (B12015 and IRT13R30)
Tianjin Natural Science Foundation (18JCZDJC31500)。
