Influence of amorphous intermediate domains on the performance of Na 2 O–Bi 2 O 3 –GeO 2 glass–ceramic anode material system

This article discusses 95[35Na 2 O–65Bi 2 O 3 ]: 5GeO 2 glass–ceramic anode material system (labeled as GC-NBG 5.0 ), which was heat-treated between T g (transition temperature) and T c (crystallization temperature) for various regimes to address severe issues with Na-ion battery technology, including poor reversible capacity, electrical conductivity, and safety (0 h, 5 h, 8 h, 12 h, and 15 h). Na 3 Bi and NaGe intermediate domains are present in GC-NBG 5.0 glass–ceramic anode material after a 12-h heat-treating regime between T g and T c . NBG 5.0 -12 h glass–ceramic anode delivers the best specific discharge capacity at 485 mA h/g, measured at 50 mA/g over a longer cycle time, which is not inferior to conventional graphite anode. The lowest cycle-dependent complex impedance characteristics ( R ct and Z w ) and a constant reversible specific discharge capacity of 442 mA h/g, however, still support the cell design even after 3000 cycles.