All‐Climate Long‐Life and Fast‐Charging Sodium‐Ion Battery using Co3S4@NiS2 Heterostructures Encapsulated in Carbon Matrix as Anode

Abstract

AbstractSodium‐ion (Na‐ion) battery is one of the research focuses because of high theoretical capacity and low cost. However, seeking for ideal anodes remains a big challenge. Here, a Co3S4@NiS2/C synthesized by in situ growing NiS2 on CoS spheres then converting to Co3S4@NiS2 heterostructures encapsulated by carbon matrix, is developed as a promising anode. Co3S4@NiS2/C as anode displays a high capacity of 654.1 mAh g−1 after 100 cycles. Even over 2000 cycles at a high rate of 10 A g−1, capacity exceeds 143.2 mAh g−1. Heterostructures between Co3S4 and NiS2 improve electron transfer as verified by density functional theory (DFT) calculations. In addition, when cycling at a high temperature of 50 °C, the Co3S4@NiS2/C anode displays 525.2 mAh g−1, while it remains 340 mAh g−1 at −15 °C, indicating all‐climate potential for using under different temperatures.