Micrometer Carbon Ball-Decorated Nanowire-Structured SnO2@C Composites as an Anode for Potassium-Ion Batteries with Enhanced Performance

For SnO2 that was used as an anode material for potassium-ion batteries (KIBs), the theoretical capacity is rarely high. However, due to the excessively huge volume expansion of SnO2 in the electrode reaction, the battery capacity decreases sharply, thus impeding its practical application. Here, potassium stannate and glucose were dissolved in the hydrothermal phase and dispersed evenly through a one-step hydrothermal method and then calcined and carbonized at a high temperature in an argon atmosphere to obtain a SnO2@C composite. To obtain an electrode with better performance, SnO2@C/MCB (micrometer carbon ball) composites were synthesized by a similar method. SnO2@C/MCB exhibited a high initial reversible capacity, splendid rate property, and cycling performance in KIBs (the initial capacity remains at 57.2% after 450 cycles). Compared with the SnO2@C material, the SnO2@C/MCB electrode has a higher electrical conductivity, smaller volume change, and better potassium storage capacity.

Automated summary

In this study, SnO2@C/MCB composites were synthesized through a one-step hydrothermal method and high-temperature calcination, showing a high reversible capacity, excellent rate performance, and cycling stability in potassium-ion batteries.