摘要
Na-CO_(2) batteries have attracted signifcant attentions due to their high energy density and efective utilization of greenhouse gas CO_(2).However,all reported Na-CO_(2) batteries employ excessive preloaded metal Na,which will lead to safety issues such as dendrite formation and short circuit.In addition,the charging mechanism of reported Na-CO_(2) batteries is not very clear.Here we report the Na-CO_(2) batteries,starting from the cathode of cheap Na2CO_(3) and multiwalled carbon nanotubes(CNTs).Due to the efective electron transfer and high reactivity,the decomposition of Na2CO_(3) and CNTs could take place under 3.8 V.Te charging mechanism of 2Na2CO_(3)+C�→4Na+3CO_(2) without any side reactions is revealed by in/ex situ techniques such as Raman,gas chromatograph,and optical microscope.Dendrite-free Na can quantitatively deposit on the Super P/Al anode because of large specifc surface area and low nucleation barrier of the anode for Na plating.Te batteries could deliver an energy density of 183 Wh kg−1(based on the whole mass of the pouch-type batteries,4 g)with stable cycling performance.Tis work reveals that safe rechargeable Na-CO_(2) batteries could be constructed by cheap Na2CO_(3) and multiwalled carbon nanotubes.
基金
Tis work was supported by the National Programs for Nano Key Project(2016YFA0202500)
the Ministry of Education(B12015)
and Tianjin Key Project(16PTSYJC00030)。
