Spindle MnCO3 tightly encapsulated by MXene nanoflakes with strengthened interface effect for lithium-ion battery

Abstract

The quality of the interface of the MnCO3-based composite electrode materials determines the application of these high-capacity anodes with abundant raw materials, non-toxic, and high thermal stability in the next generation of lithium-ion batteries. In this work, by strengthening the interface effect of composite materials, MXene encapsulated MnCO3 with spindle morphology is designed via a simple and universal two-step process involving hydrothermal synthesis and sonicated assembly in order to overcome the low conductivity and the volume change during charging and discharging of MnCO3. Spindle MnCO3 is formed using excessive salicylic acid (SA) as reducing agent, and encapsulated with MXene through hydrogen bonds. The MXene as a coating layer effectively inhibits the volume expansion of MnCO3 during charging and discharging depending on its flexible mechanical property, and improves the capacitance storage of MnCO3 due to its high electronic conductivity and fast Li+ transport capability. Therefore, MnCO3@MXene as a lithium-ion battery anode improves cycling capabilities with the capacity retention ratio of 91.2% at 5 A g−1 after 2000 cycles. The strategy of preparing MnCO3 and MXene composite materials through self-assembly of hydrogen bonds to enhance the interface effect has a good application prospect in the design of energy storage materials.