Doping of Ni and Zn Elements in MnCO₃: High‐Power Anode Material for Lithium–Ion Batteries

Abstract

Herein, Ni and Zn elements are doped simultaneously in MnCO and microspheric Mn Ni Zn CO is successfully obtained. Atomic mapping images reveal that the Ni and Zn elements have been successfully doped in MnCO and thus the prepared sample is not a mixture of MnCO , NiCO , and ZnCO . It is the first time that the atomic mapping images of ternary transition metal carbonates have been demonstrated so far. The scanning transmission electron microscopy - annular bright field (STEM-ABF) image successfully confirms the formation of oxygen vacancies in Mn Ni Zn CO , which is beneficial to improve the electrical conductivity. The evolution of the microstructure from crystal to amorphization during cycling process confirmed by the fast Fourier transform patterns effectively lowers the overpotential of the conversion reaction and accelerates the conversion between Mn and much higher valence of Mn element, contributing to the superior capacity of Mn Ni Zn CO electrode. As anode material for lithium-ion batteries, the prepared Mn Ni Zn CO exhibits excellent long-term cycling stability and outstanding rate performance, delivering the superior reversible discharge capacities of 1066 mA h g at 500 mA g after 500 cycles and 760 mA h g at 1 A g after 1000 cycles. It is the first time that Mn Ni Zn CO has been synthesized and used as anode for lithium-ion batteries so far.

Pseudocapacitive Lithium Storage in Three‐Dimensional Cobalt‐Doped MnO/Nitrogen‐Doped Reduced Graphene Oxide Aerogels as High‐Rate Anode Material

“…The 3D porous structure supplies 3D channels for electron/ion transport, contributing to much more surface pseudocapacitive lithium storage . Doping MnO with Co could enhance the migration rate of carrier and offer abundant cationic conversion reactions for lithium storage, leading to improved reaction kinetics and reversible capacity ,. To the best of our knowledge, such outstanding rate capability and cycling stability particularly in the high rate are superior to most previously reported MnO and MnO‐based hybrids (Table S1) ,,,,,…”

“…Rechargeable lithium‐ion batteries (LIBs) have been widely used in the field of portable electronics, as well as electric and hybrid vehicles for their high‐energy density, long durability, and no memory effect . Due to the low theoretical capacity of 372 mA h g −1 , however, commercial graphitic anodes cannot meet the rapidly increasing energy storage demand . Therefore, extensive efforts have been devoted to exploring advanced anode materials with both high specific capacity and excellent rate capability to replace graphitic electrode .…”

“…To solve above problems, the first strategy is to improve the intrinsic electron/ion conductivity of MnO. According to the principle of fundamentals of materials science, introducing heteroatoms in the crystal could increase the migration rate of current carrier and thus enhance the conductivity of crystal greatly ,. In this regard, doping MnO with cation ions is a good choice to improve the electrochemical performance of MnO due to an improved conductivity and reaction kinetics, as well as abundant conversion reactions deriving from multi‐metal cation ions to increase the reversible capacity .…”

“…[1][2][3][4] Due to the low theoretical capacity of 372 mA h g À 1 , however, commercial graphitic anodes cannot meet the rapidly increasing energy storage demand. [5] Therefore, extensive efforts have been devoted to exploring advanced anode materials with both high specific capacity and excellent rate capability to replace graphitic electrode. [6][7] Different from the intercalation mechanism of graphite, transitionmetal oxides (TMOs) such as CoO x , [8][9][10] FeO x , [11][12] SnO 2 , [13] and MnO x [14][15] store lithium ions through conversion reaction during cycling, leading to high theoretical capacity of 500-1000 mA h g À 1 .…”

“…According to the principle of fundamentals of materials science, introducing heteroatoms in the crystal could increase the migration rate of current carrier and thus enhance the conductivity of crystal greatly. [5,9] In this regard, doping MnO with cation ions is a good choice to improve the electrochemical performance of MnO due to an improved conductivity and reaction kinetics, [19] as well as abundant conversion reactions deriving from multimetal cation ions to increase the reversible capacity. [20][21] Furthermore, CoO with a theoretical capacity of 716 mA h g À 1 has the similar cubic crystal structure to that of MnO, [22] therefore, an appropriate amount of Co doping in MnO could have been achieved and expected to demonstrate improved lithium storage property.…”