LAUSR

Abstract Negative thermal expansion of nickel sulfide (NiS) is an underlying cause for the self-explosion of toughened glass in practical use. In this work, this undesired thermal property is rationally used to produce spiny NiS/C architectures. By liquid-nitrogen quenching NiS/C microspheres for 120 min, one can obtain a full-grown spiny structure with a well-defined NiS/C core and dense NiS prickles with large slenderness ratios. Using this architecture as an anode material in sodium-ion batteries, a relatively high specific capacity of 504.3 mAh g−1 (ca. 85.4% of its theoretical capacity value) is achieved at a current density of 200 mA g−1 after the 1000th charge-discharge cycle. Moreover, rate performance test of the 1000th-cycled cell illustrates a capacity drop from 504.3 to 445.6, then to 384.7, 319.4, and finally to 245.2 mAh g−1 as increasing the current density from 200 to 500, then to 1000, 2000, and finally to 5000 mA g−1, respectively. More detailed TEM characterization, cyclic voltammetry and electrochemical impedance measurements are conducted after the rate performance test, and the result shows that high current density can alter the contact interface between NiS architecture and electrolyte, or even change its microstructure.