Stable Li₂TiO₃ Shell–Li_1.17Mn_0.50Ni_0.16Co_0.17O₂ Core Architecture Based on an In-Site Synchronous Lithiation Method as a High Rate Performance and Long Cycling Life Lithium-Ion Battery Cathode

Abstract

A stable shell–core architecture Li2TiO3@Li1.17Mn0.50Ni0.16Co0.17O2 (LTO@LNCM) was successfully synthesized via in-site synchronous lithiation. This architecture is designed based on the fact that Li1.17Mn0.50Ni0.16Co0.17O2 will experience oxygen release and side reactions when interacted with the electrolyte and is strengthened by means of the diffusion interphase of Li2Ni x Co y Ti1–x–y O3 between Li1.17Mn0.50Ni0.16Co0.17O2 and Li2TiO3. Hence, the architecture functions as follows: (1) the Li2TiO3 shell, which is chemically stable, acts as a protective shell and (2) the Li2Ni x Co y Ti1–x–y O3 transition phase zone not only enhances the close adhesion of the core to the Li2TiO3 outer shell but also has higher Li+ ionic conductivity due to doping. LTO@LNCM showed a much higher rate capability and improved cycle performance, besides a higher initial Coulombic efficiency. In particular, LNCM with 3 mol % Li2TiO3 delivered an initial discharge capacity of 306.1 mAh·g–1 at 0.1C (Coulombic efficiency of 89.9%) and a rate capacity of 155.5 mAh·g–1 at 10C. At the same time, a reversible capacity of more than 149 mAh·g–1 after 240 cycles was achieved with only 0.11% decay per cycle at 1C rate (2.0–4.8 V). Thus, based on the collective results, we expect our LTO@LNCM with a motivating Li2Ni x Co y Ti1–x–y O3 transition phase zone to be a promising cathode material for advanced lithium-ion batteries.

Surface LiMn1.4Ni0.5Mo0.1O4 Coating and Bulk Mo Doping of Li-Rich Mn-Based Li1.2Mn0.54Ni0.13Co0.13O2 Cathode with Enhanced Electrochemical Performance for Lithium-Ion Batteries

“…Figure presents the cyclic voltammetry (CV) curves of the pristine and coated samples in the first three cycles at 0.1 mV s –1 in the voltage range of 2.0–4.8 V. In the initial cycle, there are two oxidation peaks. For the pristine sample, the first peak is situated at 4.03 V, which is attributed to the oxidation process of Ni 2+ /Ni 4+ and Co 3+ /Co 4+ . The Li 2 MnO 3 phase is invariant during this process, which can play a role to support the structure.…”

“…The surface coating can restrain lattice oxygen loss on the surface of the Li-rich cathode materials. Various coating materials have been researched previously, such as Al 2 O 3 , TiO 2 , FeO x , CeO 2 , Li x TM 3– x O 4 , Li 2 TiO 3 , LiTaO 3 , Li 1.5 Na 0.5 SiO 3 , Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 , Li 4 V 2 Mn­(PO 4 ) 4 , Mg 2 TiO 4 , Na 2 Mn­(SO 4 ) 2 , and LaPO 4 . Double-layer coating also has been reported, such as Al 2 O 3 /LiAlO 2 , Li 4 Mn 5 O 12 /MgF 2 , Li 2 ZrO 3 /poly­(3,4-ethylenedioxythiophene), Al 2 O 3 /SiO 2 , etc.…”

Multi-dimensional correlation of layered Li-rich Mn-based cathode materials

“…In addition, the binding force between the surface coating layer and the host material cannot be ignored. It is a good choice to choose a coating that is structurally compatible with a bonding effect [164] . Cycle performance of materials under Vr-1 and Vr-8, respectively [110] .…”

Demystifying the Lattice Oxygen Redox in Layered Oxide Cathode Materials of Lithium-Ion Batteries

“…Engineering the coating layer is regarded as an efficient method to boost the comprehensive electrochemical performance of the LIBs. The coating layer is considered as the protective layer at the cathode/electrolyte interface: it strengthens the crystal structural stability and adjusts the interface chemistry to mitigate the TMs’ dissolution and other side reactions; it improve the Li + diffusion; and it further mitigates the cathode materials’ degradation and electrolyte decomposition. − Therefore, many types of coating materials, including metal oxides, fluorides, and Li conductive metal oxides, have been exploited to improve electrochemical performance by impeding side reactions or improving electrical conductivity. − Usually, nonelectrochemical active coating layer such as metal oxides, -fluorides, and -phosphates, in which the metal has no variational property, have been regarded as an efficient method to boost the comprehensive electrochemical property of the LRM oxide cathode materials. With regard to these coating layers, it mainly function as a defensive layer to mitigate the cathode materials degradation and the electrolyte decomposition.…”