Ultra-large scale synthesis of Co–Ni layered double hydroxides monolayer nanosheets by a solvent-free bottom-up strategy

• Co–Ni LDHs monolayer nanosheets were prepared at an ultra-large scale at room temperature.
• The grinding of solid nitrates in morpholine produced monolayer nanosheets.
• Monolayer nanosheets were formed through the rapid consumption of water.
• The obtained Co–Ni LDHs monolayer nanosheets owned high electrochemical performance.

Monolayer nanosheets of Co–Ni layered double hydroxides (LDHs) were synthesized by an ultra-large scale strategy under very moderate condition. The simple grinding of nickel nitrate hexahydrate and cobalt nitrate hexahydrate in morpholine at room temperature produced monolayer nanosheets. At least 40 g monolayer nanosheets can be produced in one batch. The capacity for the production of nanosheets is only limited by the facility used in the laboratory. The formation of monolayered hydroxide is attributed to the complete consumption of water in the water-deficient environment by the hydrolysis reaction between water and morpholine. The water consumption would consequently eliminate the possibility of interlayer hydrogen-bonding, avoiding the stacking of already produced monolayers. Because of the monolayer state of LDHs and the synergistic effect of cobalt ions in LDHs, the nanosheets presented high electrochemical performance.