Pichaimuthu KJena AChang HSu CHu S.-FRU-SHI LIU2022-04-252022-04-25202219448244https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123936832&doi=10.1021%2facsami.1c22435&partnerID=40&md5=7e137bca63723e66d5360dfe80c02962https://scholars.lib.ntu.edu.tw/handle/123456789/606928Metal-CO2 rechargeable batteries are of great importance due to their higher energy density and carbon capture capability. In particular, Na-CO2 batteries are potential energy-storage devices that can replace Li-based batteries due to their lower cost and abundance. However, because of the slow electrochemical processes owing to the carbonated discharge products, the cell shows a high overpotential. The charge overpotential of the Na-CO2 battery increases because of the cathode catalyst's inability to break down the insulating discharge product Na2CO3, thereby resulting in poor cycle performance. Herein, we develop an ultrathin nanosheet MoS2/SnS2 cathode composite catalyst for Na-CO2 battery application. Insertion of SnS2 reduces the overpotential and improves the cyclic stability compared to pristine MoS2. As shown by a cycle test with a restricted capacity of 500 mAh/g at 50 mA/g, the battery is stable up to 100 discharge-charge cycles as the prepared catalyst successfully decomposes Na2CO3. Furthermore, the battery with the MoS2/SnS2 cathode catalyst has a discharge capacity of 35 ?889 mAh/g. The reasons for improvements in the cycle performance and overpotential of the MoS2/SnS2 composite cathode catalyst are examined by a combination of Raman, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure analysis, which reveals an underneath phase transformation and changes in the local atomic environment to be responsible. SnS2 incorporation induces S-vacancies in the basal plane and 1T character in 2H MoS2. This combined impact of SnS2 incorporation results in undercoordinated Mo atoms. Such a change in the electronic structure and the phase of the MoS2/SnS2 composite cathode catalyst results in higher catalytic activity and reduces the cell overpotential. ?catalytic activityMoS2/SnS2cathodeNa-CO2batteriesoverpotentialsulfur vacanciesCatalyst activityCathodesElectronic structureIV-VI semiconductorsLayered semiconductorsLithium compoundsMolybdenum compoundsNanosheetsSecondary batteriesSemiconducting tin compoundsSodium CarbonateSodium sulfideSulfur compoundsX ray absorptionX ray absorption near edge structure spectroscopyX ray photoelectron spectroscopyCapture capabilityCathode catalystComposite cathodeCycle performanceHigher energy densityNa-CO2batteryOverpotentialSulfur vacanciesUltrathin nanosheetsCarbon dioxide[SDGs]SDG7[SDGs]SDG13journal article10.1021/acsami.1c22435350607102-s2.0-85123936832