A synergetic SnSb-amorphous carbon composites prepared from polyesterification process as an ultrastable potassium-ion battery anode

Combining the stability of amorphous carbon with the high-capacity contribution of metal alloys need explicit structural engineering design so that the beneficial contribution of each constituent material can lead to the desired synergistic electrochemical performance. Here, we report the synthesis of ultrafine SnSb embedded in meso/microporous amorphous carbon (SnSb@MAC) through a polyesterification strategy. As the anode of potassium ion batteries (PIBs), SnSb@MAC composite exhibits better electrochemical performance relative to that of SnSb nanocrystals (SnSb NCs) and MAC. In particular, the composite has an excellent cycle life, with a reversible capacity of similar to 200 mA h g(-1) after 5000 cycles, being the longest life reported for the SnSb-C composites. The K+-transport mechanism of the composite is experimentally verified through in-situ X-ray diffraction, ex-situ TEM and selected area electron diffraction (SAED) and demonstrate the high synergy between SnSb and MAC resulted in the satisfactory storage performance. Finally, the full cell constructed by coupling the SnSb@MAC anode with an organic cathode (perylene-3,4,9,10-tetracarboxylic dianhydride, PTCDA) exhibits a maximum energy density of 228.9 W h kg(-1) and a maximum power output of 6150 W kg(-1) as well as 177 mA h g(-1) along with a current density of 400 mA g(-1) after 400 cycles.

Automated summary

The synthesis of SnSb@MAC composite as the anode for potassium ion batteries showed excellent electrochemical performance, with long cycle life and high storage capacity. In particular, the composite demonstrated a reversible capacity of around 200 mA h g(-1) after 5000 cycles, and the K+-transport mechanism was experimentally verified to show high synergy between SnSb and MAC.