The growth of sodium dendrites and the dissolution of organic cathodes are the two main challenges hindering the development of sodium organic batteries (SOBs). Here,Jia Dianci, Wang Xingchao, Sun Ying, et al., Xinjiang UniversityA multifunctional Janus diaphragm (H-bn@pp@c) using interface engineering strategy was proposed to solve the SOBS problem. The carbon layer facing the organic cathode acts as a barrier to capture dissolved organic matter and improve its utilization. At the same time, the H-Bn layer facing the Na anode has high thermal conductivity and mechanical strength, which alleviates the occurrence of local temperature "hot spots" and promotes the formation of Naf-Sei-rich cells, thereby inhibiting the growth of dendrites.
Thus, the Janus septum is able to cycle stably for 1000 h at 3 mA2. Organic cathodes such as dibenzo[b,i]thiophene-5,7,12,14-tetraone (DTT), benzene-5,7,12,14-tetraone and cup[4]quinone were separators with Janus separators, which exhibited high capacity and significant cycling performance.
Figure 1Effect of the Janus diaphragm on the DTT cathode
In summary, this work demonstrates an interface engineering strategy that uses a Janus separator to simultaneously inhibit sodium dendrite growth and organic cathode dissolution of SOBs. The H-Bn coating has good wettability and thermal conductivity, which promotes the formation of Naf-rich Sei, which results in uniform Na+ flux and prevents the formation of Na dendrites. In addition, the carbon coating acts as a conductive barrier, which can effectively improve the utilization rate of electroactive materials and accelerate the kinetics.
As a result, the Janus separator is able to achieve a long cycle life of more than 1000 hours for Na Na batteries with a stable overpotential of around 14 mV. A Na DTT battery with a Janus separator exhibits 500 at 1 mA g 285 currentHigh specific capacity of 2 mAh g 1. In addition, two other organic materials (PT and C4Q) using the Janus separator also exhibited enhanced capacity and cycling stability.
Figure 2Battery performance
combining janus separator and organic cathode for dendrite-free and high-performance na-organic batteries,advanced functional materials2023 doi: 10.1002/adfm.202309552