Strain engineering of Bi2S3 microspheres via organic intercalation enabled high performance sodium storage

Abstract

Conversion or alloying-type layered metal chalcogenides, which hold great promise as anodes for sodium storage, encounter a significant challenge of volume expansion due to the accumulation of inner strain during the charge–discharge process. This issue leads to severe stress concentration and necessitates urgent attention in terms of dispersing the distribution of inner strain through advanced strain engineering techniques. In this study, we have successfully fabricated Bi2S3-TTAB microspheres composed of Bi2S3 nanorods intercalated with tetradecyltrimethylammonium bromide (TTAB). By periodically inserting the soft TTAB into the interlayer of Bi2S3, we effectively isolate and confine the Bi2S3 layers while simultaneously expanding the interlamellar spacing. This innovative approach disperses and alleviates the inner strain of Bi2S3 at an atomic level, thereby ensuring electrode stability. As a competitive conversion-alloying-type anode for sodium-ion batteries, the Bi2S3-TTAB microspheres demonstrate remarkable performance in terms of high rate capacities and cycle stability (208.4 mAh g−1 at 15 A g−1; 4910 cycles at 10 A g−1 with 87.8 % capacity retention). This exceptional Na-ion storage capability enables the utilization of Bi2S3-TTAB combined with active carbon as an advanced sodium ion capacitor that demonstrates impressive energy and power densities (144.0 Wh kg−1 and 5.0 kW kg−1).