Assembly of MnCO 3 nanoplatelets synthesized at low temperature on graphene to achieve anode materials with high rate performance for lithium-ion batteries

Low Barriers and Faster Electron/Ion Transport Rates through the Ga2O3/MnCO3 Anode with a Heterojunction Structure for Lithium-Ion Batteries

Electrode stability can be controlled to a large extent by constructing suitable composite structures, in which the heterojunction structure can affect the transport of electrons and ions through the effect of the interface state, changed band gap width, and the electric field at the interface. As a promising electrode material, the Ga-based material has a conversion between solid and liquid phases in the electrochemical reaction process, which endows it with self-healing properties with the structure and morphology. Based on these, the Ga2O3/MnCO3 composite was successfully synthesized with a heterogeneous structure by introducing a Ga source in the hydrothermal process. Benefitting from the acceleration effect of the internal electric field and the narrower band gap at the interface, a high-capacity Ga2O3/MnCO3 composite electrode (1112 mAh·g-1 after 225 cycles at 0.1 A·g-1 and 457.1 mAh·g-1 after 400 cycles at 1 A·g-1) can be achieved for lithium-ion batteries. The results can provide a reference for the research and preparation of electrode materials with high performance.

A ternary oxygen-vacancy abundant ZnMn2O4/MnCO3/nitrogen-doped reduced graphene oxide hybrid towards superior-performance lithium storage

Transition metal oxides (TMOs) and metal carbonates exhibit high specific capacity, abundant reserves on Earth, and environmental friendliness as anode materials for lithium-ion batteries (LIBs). However, their poor electrical conductivity and serious volume expansion lead to rapid capacity decay. Herein, a stable and highly conductive composite of an oxygen-vacancy abundant nitrogen-doped reduced graphene oxide (NG) encapsulated ZnMn2O4/MnCO3 (ZnMn2O4/MnCO3/NG) hybrid is successfully fabricated, which can provide more spaces for rapid ion diffusion and corroborate fast electron transport. The ZnMn2O4/MnCO3/NG hybrid exhibits an incredible reversible capacity (916 mA h g-1 at 0.1 A g-1), preeminent cycling stability (800 mA h g-1 at 1 A g-1 after 300 cycles) and outstanding rate capability (459 mA h g-1 at 2 A g-1). The excellent lithium storage performance of ZnMn2O4/MnCO3/NG is attributed to the synergistic effect between ZnMn2O4 and MnCO3, the addition of nitrogen and oxygen defects, and the stable structures of NG, which relieve the volume expansion of the electrode material, improve the electronic conductivity and enhance structural stability and surface capacitive response. This work provides a new idea for constructing oxygen-vacancy abundant NG encapsulated bimetal oxides for energy storage of LIBs.

Electrochemical Activation of Oxygen Vacancy-Rich Nitrogen-Doped Manganese Carbonate Microspheres for High-Performance Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (ZIBs) are considered as one of the ideal devices for large-scale energy storage because of their safety, low cost, and nontoxicity. Unfortunately, the choice of cathode materials for ZIBs is still limited. Herein, a novel oxygen vacancy-rich nitrogen-doped MnCO₃ (MnCO₃@N) microsphere is reported as a cathode material for rechargeable ZIBs, which displays a relatively high reversible capacity of 171.6 mAh g^-1 at 100 mA g^-1, outstanding rate performance, and long-term cyclic stability up to 1000 cycles at 1000 mA g^-1. The better electrochemical performances of MnCO₃@N should be attributed to the introduction of oxygen vacancies in the MnCO₃ microcrystal by nitrogen doping, which not only improves the conductivity of MnCO₃ microspheres but also creates more active sites for zinc-ion diffusion. In addition, the energy storage mechanism of the MnCO₃@N microspheres is systematically investigated. During the initial charge process, the MnCO₃@N microspheres are activated to form MnO@N due to the insertion of Zn²⁺, and partial MnO@N is further oxidized into layered-type MnO₂@N, which becomes a part of the active material for subsequent energy storage. This work not only provides a new insight for the ZIB cathode but also deepens the understanding of the energy storage mechanism of carbonate materials.

Study for the preparation of Cu2+-doped twin spherical MnCO3 structure as an anode material for high-performance lithium-ion batteries

Cu2+-Doped twin spherical MnCO3 microstructure was prepared, characterized and used as an anode for the lithium-ion battery. After 600 cycles, a reversible capacity of 810 mA h g−1 was retained. Excellent rate property and cyclability were attained.

Heterojunction-structured MnCO3@NiO composites and their enhanced electrochemical performance

The conductivity and stability of materials have always been the main problems hindering the development of lithium-ion battery applications. Here, we successfully construct MnCO3@NiO composites with unique heterogeneous structure via the epitaxial growth of porous NiO nanosheets (thickness: ∼125 nm) on MnCO3 microspheres (diameter: ∼3 μm) to be the anode of lithium-ion batteries. The synergistic effect provided by this special heterogeneous structure effectively improves the electrochemical kinetics, specific surface area as well as structural stability of the composites, finally resulting in predictable enhanced comprehensive electrochemical performance. The electrochemical results show that the MnCO3@NiO composites exhibit a reversible discharge capacity of 624 mA h g-1 at a current density of 1.0 A g-1 up to 300 cycles.

Construction of Mn-Zn binary carbonate microspheres on interconnected rGO networks: creating an atomic-scale bimetallic synergy for enhancing lithium storage properties

Transition metal carbonates (TMCs), as promising anode materials for high-performance lithium ion batteries, possess the advantages of abundant natural resources and high electrochemical activity; however, they suffer from poor Li+/e- conductivities and serious volume changes during the charge/discharge process. Constructing multicomponent carbonates by introducing binary metal atoms, as well as designing a robust structure at the micro and nanoscales, could efficiently address the above problems. Therefore, single-phase MnxZn1-xCO3 microspheres anchored on 3D conductive networks of reduced graphene oxide (rGO) are facilely synthesized via a one-pot hydrothermal method without any structure-directing agents or surfactants. Due to the well-designed architecture and atomic-scale bimetallic synergy, the MnxZn1-xCO3/rGO composites show superior lithium storage capacity, good rate capability and ultra-long cycling performance. Specifically, the Mn2/3Zn1/3CO3/rGO composites could deliver a high capacity of 1073 mA h g-1 at 200 mA g-1. After 1700 cycles at a high rate of 2000 mA g-1, a stable capacity of 550 mA h g-1 can be maintained with the capacity retention approaching 88.6%. Density functional theory (DFT) calculations indicate that the partial Zn substitution in MnCO3 could significantly decrease the band gap of the crystal, resulting in great improvement of electric conductivity. Moreover, the commercial potential of the MnxZn1-xCO3/rGO composites is investigated by assembling full cells, suggesting good practical adaptability of the composite anodes. This work would provide a feasible and cost-efficient method to develop high-performance anodes and stimulate many more related research studies on TMC-based electrodes.