Ren Dongyan, Tang Xin, Wang Qiqiang, Du Haifeng, Ding Ling
Department of Materials and Construction, Mianyang Vocational and Technical College, Mianyang 621010, Sichuan, China.
State Key Laboratory of Environment-Friendly Energy Materials, School of Material and Chemistry, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China.
ACS Omega. 2024 Aug 6;9(33):35920-35928. doi: 10.1021/acsomega.4c05040. eCollection 2024 Aug 20.
Poly(ethylene oxide) (PEO) electrolytes usually suffer from low room temperature (RT) ionic conductivity and a narrow voltage window, which limits the improvement of energy density and practical applications in all-solid-state batteries. Composite polymer electrolytes (CPEs) are regarded as the common method to reduce the crystallinity of polymers and increase the lithium ion conductivity. Compared with active or inert ceramic material fillers in previous studies, aluminum-lithium alloy fillers are used to prepare composite electrolytes in this study, showing excellent performance at room temperature. The conductivity of the PEO-based electrolytes increases by a factor of 3.62-3.62× 10 S cm at RT with 5 wt % Al-Li alloy. The transference number of Li is increased to 0.524. The characteristics of the Al-Li alloy and higher conductivity enable the composite electrolyte to stabilize the interface with the electrodes, reducing the polarization of solid-state batteries. The all-solid-state Li/PEO-5%/LiFePO cells show the highest initial discharge capacity of 153 mAh g and the highest stable discharge capacity of 147 mAh g with the initial Coulombic efficiency of more than 100%. It also exhibits the best rate capacity and cycle performance (90% capacity retention rate after 100 cycles).
聚环氧乙烷（PEO）电解质通常存在室温离子电导率低和电压窗口窄的问题，这限制了全固态电池能量密度的提高和实际应用。复合聚合物电解质（CPEs）被认为是降低聚合物结晶度和提高锂离子电导率的常用方法。与以往研究中的活性或惰性陶瓷材料填料相比，本研究采用铝锂合金填料制备复合电解质，在室温下表现出优异的性能。含5 wt%铝锂合金的PEO基电解质在室温下的电导率提高了3.62至3.62×10 S cm。Li的迁移数增加到0.524。铝锂合金的特性和较高的电导率使复合电解质能够稳定与电极的界面，降低固态电池的极化。全固态Li/PEO-5%/LiFePO电池的最高初始放电容量为153 mAh g，最高稳定放电容量为147 mAh g，初始库仑效率超过100%。它还表现出最佳的倍率性能和循环性能（100次循环后容量保持率为90%）。
