<p>MoS₂ nanosheets as a quintessential layered solid lubricant has been demonstrated ultra-low friction in a dry environment due to the weak van der Waals forces arising from interlayer sliding. Nonetheless, MoS₂ nanosheets as lubricant additives are susceptible to agglomeration and complicating the attainment of ultra-low friction under air conditions. Herein, the modification and refining of MoS₂/CuS nanocomposites were achieved by a one-step liquid-phase laser irradiation technique in atmospheric conditions, which can result in an aqueous-based composite lubricant with excellent dispersion in water. Ball-on-disk rotational friction tests demonstrated that the optimized MoS₂/CuS composite aqueous lubricant exhibited excellent anti-wear and friction-reducing characteristics, achieving an ultra-low friction coefficient (COF) of ~ 0.06 and a wear scar diameter (WSD) reduction of 49.5% compared to pure deionized water. Such ultrafine nanocomposites can efficiently penetrate the tribological contact zone, thereby preventing direct contact between sliding interfaces. More importantly, the layered structures of both MoS₂ and CuS components facilitate interlayer sliding under shear stress, collectively mitigating the friction and wear. This study could resolve the challenges associated with the dispersion and aggregation of flaky MoS₂ in lubricants, while also tackling the limitations of low load-carrying capacity and inadequate lubrication performance encountered by aqueous lubricants in practical applications.</p> Graphical Abstract