Electrode structure enabling dendrite inhibition for high cycle stability quasi-solid-state lithium metal batteries

Abstract

Lithium (Li) metal batteries (LMBs) are widely regarded as the ultimate choice for the next generation of high-energy–density batteries. However, the uncontrollable growth of Li dendrites formed by inhomogeneous deposition seriously hinders its commercialization. Although many studies have achieved significant results in inhibiting the formation of Li dendrites, it is still impossible to eradicate them completely. Therefore, regulating the deposition behavior, such as the growth direction of unevenly deposited Li, is preferable to unilaterally suppressing them in some cases. Here we report a structured anode that can confine the deposited Li within holes and tune it to become vertical-up/horizontal-centripetal mixed growth mode by optimizing the electric field/Li+ concentration gradient. The Li+ adsorbed by the poly(amic acid) (PAA) insulating layer coated on the anode surface can form the Li+ concentration gradient pointing to the center of the hole. Combined with the special electric field formed by the hole structure, it is favorable for the Li+ to move into the vertically arrayed holes and simultaneously deposit on the bottom and walls. Furthermore, both in-situ and ex-situ observations confirm that the growth mode is changed and the Li deposition morphology is denser, which can greatly delay capacity fading and prolong cycle life in both liquid and quasi-solid-state LMBs. All the results show that the novel anode provides a new perspective for deep research into solid-state LMBs.