Electrochemical behavior of nanostructured NiO@C anode in a lithium-ion battery using LiNi⅓Co⅓Mn⅓O2 cathode

Abstract

A NiO@C composite anode is prepared through an alternative synthesis route involving precipitation of a carbon precursor on NiO nanopowder, annealing under argon to form a Ni core, and oxidation at moderate temperature to get metal oxide particles whilst retaining carbon and metallic Ni in traces. The electrode reversibly reacts in lithium cells by the typical conversion process occurring in a wide potential range with the main electrochemical activity at 1.3 V vs.Li + /Li during discharge and at 2.2 V vs. Li + /Li during charge. The NiO@C material exhibits highly improved behavior in a lithium half-cell compared to bare NiO due to faster electrode kinetics and superior stability over electrochemical displacement, leading to a reversible capacity approaching 2 800 mAh g −1 , much enhanced cycle life and promising rate capability. The applicability of the NiO@C anode is further investigated in a lithium-ion NiO@C/LiNi⅓Co⅓Mn⅓O2 cell, which operates at about 2.5 V delivering about 160 mAh g −1 with respect to the cathode mass. The cell exhibits stable response upon 80 cycles at a C/2 rate with coulombic efficiency ranging from 97% to 99%.

Synthesis of a High-Capacity α-Fe2O3@C Conversion Anode and a High-Voltage LiNi0.5Mn1.5O4 Spinel Cathode and Their Combination in a Li-Ion Battery

“…On the other hand, the EDS analyses actually reveal the complete reduction of the maghemite precursor (Figure 2c) to metallic iron along with the formation of carbon with a weight ratio of 23% during pyrolysis (Figure 2f), which is lowered to about 6% after the final oxidation of the intermediate to α-Fe 2 O 3 @C (Figure 2i), in which all elements are homogeneously distributed (see the corresponding map in the inset of Figure 2i). According to our previous report on a conversion electrode based on nickel oxide, 35 we may expect that the morphology observed for α-Fe 2 O 3 @C in Figure 2 would ensure an optimal electric contact between the α-Fe 2 O 3 grains and buffer volume variation, thus allowing an improved electrochemical process in the Li-cell. 46 In addition, the encapsulation of nanoparticles into aggregates with a microsize can actually ensure a suitable electrode tap density and, at the same time, mitigate the electrolyte decomposition and increase the cell efficiency.…”

“…This pathway, previously adopted for achieving a NiO@C electrode, leads to carboncoated metal oxide particles suitable for battery application and includes simple experimental steps. 35 In addition, pristine γ-Fe 2 O 3 and sucrose are cheap and widely available precursors, thus possibly providing a scalable two-step method with a moderate economic impact to prepare an efficient and alternative iron oxide anode for use in Li-ion batteries. 28 The structure, morphology, and elemental composition of the α-Fe 2 O 3 @C material are provided in oxidation to hematite (α-Fe 2 O 3 ) upon mild treatment under air.…”

“…28,34 We have lately adopted a facile two-step synthesis to prepare a C-coated nanostructured NiO anode successfully used in a novel lithium-ion battery using the LiNi 1/3 Co 1/3 Mn 1/3 O 2 layered cathode. 35 However, the voltage hysteresis and a working voltage higher than that of conventional graphite may actually jeopardize the potential use of conversion electrodes in a practical full Li-ion cell. 35 On the other hand, high-voltage cathodes exploiting the spinel-type structure and a Li x M y N (2−y) O 4 chemical formula (where M and N are transition metals, e.g., Ni, Mn, or Fe) appeared as the ideal candidates for enabling the use of the Li-conversion anodes.…”

“…35 However, the voltage hysteresis and a working voltage higher than that of conventional graphite may actually jeopardize the potential use of conversion electrodes in a practical full Li-ion cell. 35 On the other hand, high-voltage cathodes exploiting the spinel-type structure and a Li x M y N (2−y) O 4 chemical formula (where M and N are transition metals, e.g., Ni, Mn, or Fe) appeared as the ideal candidates for enabling the use of the Li-conversion anodes. 36−39 Among them, LiNi 0.5 Mn 1.5 O 4 revealed the most suitable performance in the lithium cell, namely, a working voltage of 4.8 V, a theoretical capacity of 147 mA h g −1 , and high rate capability.…”

High Performance Nickel Based Electrodes in State-of-the-Art Lithium-Ion Batteries: Morphological Perspectives

“…Even with a unique morphology, the initial lithiation capacity of Li in conversion anodes is still much larger than the de-lithiation capacity. However, efforts to increase the usability of conversion-type materials for Li-ion full cells, such as a Lirich cathode material, material incorporation with carbon, and pre-lithiation of conversion anodes, are still being made (Qiu et al, 2018;Wei et al, 2020).…”