| Abstract [eng] |
n this work, polymers and their composite electrodes for aqueous sodium-ion batteries were studied. The adhesive properties of polymers were investigated by placing metal disks coated with polymers and their composites in electrolyte solutions with neutral and acidic pH. The three best performing materials (PVB, PGPQ and PB67) identified during the study were further investigated as binders in NTP and NVTP electrodes and compared with the commonly used PVDF. CV showed that the polymers are not electrochemically active, while galvanostatic cycling showed that the capacity of the NTP based composites pressed on steel mesh, containing PVDF, reached 90 mAh/g and retained 67.97% of the initial capacity after cycling, while PVB showed 105 mAh/g and retained 41%, PGPQ – 101 mA/g and 52.18%, PB67- 84 mAh/g and 53.59%. Cycling was also performed using electrodes coated on steel foil, where due to poor adhesion, PVDF and PB67-containing electrodes detached from the surface, while PVB and PGPQ electrodes showed initial capacities of 96 mAh/g and 82 mAh/g and 24.63 and 30.84% ​​capacity retention after 300 cycles, respectively. Identical studies were also performed with NVTP electrodes using the same selected binders and similar capacities of about 40 mAh/g were obtained in the electrodes pressed into steel mes, the electrodes cast on foil behaved similarly to the NTP case with the exception of PVB, where part of the electrode dislodged from the surface during cycling, resulting in a drastic decrease in the electrode capacity. The electrode surfaces before and after cycling were examined using SEM. The images showed that PVDF electrodes had many cracks on the surface after cycling, PVB slightly less, and PGPQ the least. After analyzing these data, PGPQ was selected as the optimal binder for composite aqueous sodium-ion batteries. |
