CHIH-JUNG CHENYang J.-JChen C.-HWei D.-HHu S.-FRU-SHI LIU2021-08-032021-08-03202020403364https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083622092&doi=10.1039%2fd0nr00971g&partnerID=40&md5=51f163fa4881eff97063b012cd2708a3https://scholars.lib.ntu.edu.tw/handle/123456789/575844Herein, ruthenium (Ru) nanoparticles were anchored on carbon nanotubes (Ru/CNTs) functionalized as catalyst cathodes for non-aqueous Li-CO2 cells. For cycling tests through a low cut-off capacity (100 mA h g-1), the origin of battery deterioration resulted from the accumulation of Li2CO3 discharging products on catalytic surfaces, identical to the observations in previous studies. However, the Li-CO2 cells in this work showed a sudden death within several cycles of high cut-off capacity (500 mA h g-1), and no Li2CO3 residues were investigated on the cathode. In contrast, Li dendrites and passivation materials (LiOH and Li2CO3) were generated on Li anodes upon cycling at a limited capacity of 500 mA h g-1, which dominantly contributed to the battery degradation. A Li foil-replacement method was adopted to make the Ru/CNT cathode perform continuous 100 cycles under a cut-off capacity of 500 mA h g-1. These results indicate that not only Li2CO3 residues blocked on the active sites of the cathode but also Li dendrites and passivation materials produced on the anode caused Li-CO2 battery deterioration. Moreover, in the present work, a carbon thin film was deposited on Li metal (C/Li) by a sputtering system for suppressing the dendrite formation upon cycling and promoting the defense of the H2O attack from the electrolyte disintegration. The Li-CO2 cell with a Ru/CNT catalyst and a C/Li anode revealed an improved electrochemical stability of 115 cycles at a limited capacity of 500 mA h g-1. This proto strategy provided a significant research direction focusing on Li anodes for elevating the Li-CO2 battery durability. ? 2020 The Royal Society of Chemistry.Anodes; Carbon dioxide; Catalysts; Cathodes; Disintegration; Electrolytes; Lithium batteries; Lithium compounds; Passivation; Ruthenium compounds; Battery degradation; Catalytic surfaces; Dendrite formation; Electrochemical stabilities; Limited capacity; Passivation materials; Replacement methods; Sputtering systems; Lithiumjournal article10.1039/d0nr00971g322390282-s2.0-85083622092