One-pot hydrothermal synthesis of core-shell structured MnCO3@C as anode material for lithium-ion batteries with superior electrochemical performance

- Cubic MnCO3@CandpureMnCO3weresynthesizedbyone-pothydrothermalmethod.
- MnCO3@C showed enhanced capacity retention and rate property than pure MnCO3.
- The phase evolution of MnCO3 electrodes during discharge process were analyzed by IR spectroscopy.

Cubic MnCO3@C composite was first synthesized using one-pot hydrothermal method. The prepared cubic MnCO3@C presented a homogeneous core-shell structure, which was composed of cubic MnCO3 as core, a mixture of amorphous carbon and MnCO3 as shell, and a separating interlayer. Compared to pure MnCO3, core-shell structured MnCO3@C exhibited better cycling stability, rate performance and recovery capability. It delivered a reversible capacity of 1020 mAh g−1 which was 94.7% of the initial capacity, and a recovery capacity of 862 mAh g−1 after 80 cycles under current density from 100 mA g−1 to 10000 mA g−1. The superior electrochemical performance of MnCO3@C could be attributed to the improved electronic conductivity and suppressed particle aggregation during the conversion reaction. Voltage profile and cyclic voltammetry test results showed active material transformation in both anode materials during the cycling process. Furthermore, the infrared spectra at different discharge/charge states showed that the conversion reactions of MnCO3 included not only the transition from MnCO3 to Mn, but also a further reaction from Li2CO3 to Li2O.