Synthesis of Hierarchically Porous SnO₂ Microspheres and Performance Evaluation as Li-Ion Battery Anode by Using Different Binders

We have prepared nanoporous SnO2 hollow microspheres (HMS) by employing the resorcinol-formaldehyde (RF) gel method. Further, we have investigated the electrochemical property of SnO2-HMS as negative electrode material in rechargeable Li-ion batteries by employing three different binders-polyvinylidene difluoride (PVDF), Na salt of carboxy methyl cellulose (Na-CMC), and Na-alginate. At 1C rate, SnO2 electrode with Na-alginate binder exhibits discharge capacity of 800 mA h g(-1), higher than when Na-CMC (605 mA h g(-1)) and PVDF (571 mA h g(-1)) are used as binders. After 50 cycles, observed discharge capacities were 725 mA h g(-1), 495 mA h g(-1), and 47 mA h g(-1), respectively, for electrodes with Na-alginate, Na-CMC, and PVDF binders that amounts to a capacity retention of 92%, 82%, and 8% . Electrochemical impedance spectroscopy (EIS) results confirm that the SnO2 electrode with Na-alginate as binder had much lower charge transfer resistance than the electrode with Na-CMC and PVDF binders. The superior electrochemical property of the SnO2 electrode containing Na-alginate can be attributed to the cumulative effects arising from integration of nanoarchitecture with a suitable binder; the hierarchical porous structure would accommodate large volume changes during the Li interaclation-deintercalation process, and the Na-alginate binder provides a stronger adhesion betweeen electrode film and current collector.