The lithium ion battery (LIB) is the most important energy storage device since the last decade, which is due to the excellent characteristics of operating voltage, cycle life and its low self-discharge rate. [1]. Nevertheless lithium ion batteries are gradually reaching their theoretical limits, in terms of energy density, power density as wells as durability and cost [2, 3]. Because electronic portables devices as wells as electric vehicles demand high energy density batteries, the development of next generation batteries has strongly increased during the recent years. To achieve high energy densities in these systems, lithium is used as anode due to its outstanding properties regarding the theoretical specific capacity (3860 mAh g^-1) and the negative electrochemical potential (-3.04V vs. standard hydrogen electrode). However, the rapid degradation as well as safety issues related to the morphological transformation from dense to porous lithium metal affect the cell performance [4-7].

In this work, we studied the influence of the test conditions on the morphological changes on the lithium anode and cycle life of the lithium metal battery (LMB). For this, we carried out ex-situ measurements for a better understanding of the morphological changes of the anode material. Depending on the applied conditions, the cycle life of the system was improved with lower capacity fading and at the same time the morphological changes of the lithium anode were suppressed.

In the second part, the investigation is focused into the degradation of different nickel-rich cathode materials. Most of the studies on lithium metal batteries are based on the degradation of the lithium anode, however, here; it could be shown that aging of the cathode material is an important part for the development of the LMB. The results showed a good cycle performance over 300 cycles with relative low capacity fading of the LMB with all the implemented cathodes. The electrochemical data analysis showed the degradation of the cathode material, controlling at the same time the morphological changes of the lithium anode.

Literature

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