Reaching Highly Stable Specific Capacity with Integrated 0.6Li₂MnO₃ : 0.4LiNi_0.6Co_0.2Mn_0.2O₂ Cathode Materials

Abstract

The work described herein was performed to find guidelines for the optimal selection of high-specific-capacity cathode materials for Li-ion batteries. In this study, we compared the electrochemical behavior of three cathode materials working over wide potential domains in Li cells: Li (as a reference material). The first two compositions are Li-and Mnrich cathode materials that contain Li 2 MnO 3 and LiNi x Co 1-x-y Mn y O 2 components, as established by structural analysis using X-ray and electron diffraction. The main focus was the possibility to obtain a stable capacity and average voltage while working over a wide potential domain, in order to extract high specific capacity. The three materials were prepared through the selfcombustion reaction and were characterized by using SEM, ICP, HRTEM, and electrochemical techniques. Li 1.2 Ni 0.24 Co 0.08 Mn 0.48 O 2 cathodes operating over the potential range 2.0-4.6 V vs. Li demonstrated stable specific capacities greater than 200 mAh g À1 and stable average voltages, thus rivaling LiNi 0.6 Co 0.2 Mn 0.2 O 2 and Li 1.2 Ni 0.16 Co 0.08 Mn 0.56 O 2 cathodes in terms of electrochemical performance. The consequences of these findings are discussed herein. Li-and Mn-rich cathode materials may be advantageous compared to Ni-rich cathode materials in terms of cost and safety.[a] Dr.

Investigation of Li1.17Ni0.20Mn0.53Co0.10O2 as an Interesting Li‐ and Mn‐Rich Layered Oxide Cathode Material through Electrochemistry, Microscopy, and In Situ Electrochemical Dilatometry

“…It should be noted that this is a unique composition of Li and Mn‐rich NCM compound containing the transition metals (Ni, Mn and Co) along with Li, which is not yet reported. It is well known that the fine composition of these materials play an important role in their electrochemical performance . The HENCM materials are known to deliver high capacities, but suffer from poor cycling, which can be clearly seen from Table .…”

“…It is well known that the fine composition of these materials play an important role in their electrochemical performance. [38,39] The HENCM materials are known to deliver high capacities, but suffer from poor cycling, which can be clearly seen from Table 1. However, the advantage of this synthesized material Li 1.17 Ni 0.20 Mn 0.53 Co 0.10 O 2 is that it exhibited initial low capacity and the capacity achieved after 100 cycles is higher than that obtained for other HENCM cathode materials, as presented in Table 1.…”

“…In several previous works it was found that the content of Ni in these materials influences their stability. Within the commonly explored family of Li 1.2 Ni 0.1+x Co 0.1+x Mn 0.4+y O 2 cathodes (y+2x=0.2), it was found that at Ni stoichiometry around 0.2 and above, these materials exhibit an interesting stabilization effect . For the present study, we have designed and prepared a new composition, Li 1.17 Ni 0.2 Mn 0.53 Co 0.1 O 2 by a sol‐gel method using citric acid as the chelating agent followed by annealing at 900 °C for 15 h. In this material, the amount of Co and Li are lower as compared to the well‐known and widely explored Li 1.2 Ni 0.13 Mn 0.53 Co 0.13 O 2 cathode material, which can serve as a benchmark for HENCM cathode materials with Li/transition metals ratio is around 1.5.…”

“…Within the commonly explored family of Li 1.2 Ni 0.1 + x Co 0.1 + x Mn 0.4 + y O 2 cathodes (y + 2x = 0.2), it was found that at Ni stoichiometry around 0.2 and above, these materials exhibit an interesting stabilization effect. [38,39] For the present study, we have designed and prepared a new composition, Li 1.17 Ni 0.2 Mn 0.53 Co 0.1 O 2 by a sol-gel method using citric acid as the chelating agent followed by annealing at 900°C for 15 h. In this material, the amount of Co and Li are lower as compared to the well-known and widely explored Li 1.2 Ni 0.13 Mn 0.53 Co 0.13 O 2 cathode material, which can serve as a benchmark for HENCM cathode materials with Li/transition metals ratio is around 1.5. The new Li and Mn-rich cathode material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and was tested electrochemically in Li battery prototypes containing Li metal anodes and standard electrolyte solutions (coin cells configuration).…”

Tuning of Ni, Mn, and Co (NMC) Content in 0.4(LiNixMnyCozO2)·0.4(Li2MnO3) toward Stable High-Capacity Lithium-Rich Cathode Materials

“…particularly, the higher Ni-containing NMC compositions are less explored. 19,22 Hence, we decided to carry out a systematic study on 0.4(LiNi x Mn y Co z O 2 )•0.4(Li 2 MnO 3 ) series involving NMC compositions NMC-333, NMC-442, NMC-532, NMC-622, and NMC-811. An increase in nickel content while decreasing the cobalt and manganese content in layered cathodes results in reduction of oxygen evolution as the Ni−O (391.6 kJ mol −1 ) bond energy is higher than the Co−O (368 kJ mol −1 ) bond energy.…”