(Invited) Reducing Capacity and Voltage Decay of Co-Free Positive Electrode Materials for Lithium Batteries

Abstract

State-of-the-art batteries for electric vehicles are limited to specific energies below 300 Wh kg-1, shortcoming the high requirements for extended EV driving ranges [1]. Due to their high specific capacity and operative voltage, Li-rich layered oxide (LRLO) positive electrode materials are expected to enable very high specific energies, beyond 350 Wh kg-1 at the electrode stack level even without cobalt being present in their formulation [2]. More specifically, Li1.2Ni0.2Mn0.6O2 (LRNM) offers a large specific capacity (250 mAh g-1) and therefore, higher energy density than any other existing Co-free cathode material.However, its practical use is impeded by the low first cycle Coulombic efficiency, the rather low rate capability and, most critically, the pronounced capacity and voltage fading upon cycling [3]. Herein, we demonstrate as the design of the cathode-electrolyte interphase (CEI) using appropriate electrolytes strongly reduces these drawbacks enabling Li metal and Li-ion cells showing excellent long-term cycling performance due to mitigated the capacity fading and voltage decay.References X. Zeng, M. Li, D. Abd El‐Hady, W. Alshitari, A. S. Al‐Bogami, J. Lu and K. Amine, Adv. Energy Mater. 2019, 9, 1900161.R. Schmuch, R. Wagner, G. Hörpel, T. Placke and M. Winter, Nat. Energy. 2018, 3, 267.J. Zheng, S. Myeong, W. Cho, P. Yan, J. Xiao, C. Wang, J. Cho and J.-G. Zhang, Adv. Energy Mater. 2017, 7, 1601284.