Sn-stabilized Li-rich layered Li(Li_0.17Ni_0.25Mn_0.58)O₂ oxide as a cathode for advanced lithium-ion batteries

Abstract

5Li-rich layered oxides have been intensively investigated as cathode for high energy lithium-ion batteries. However, oxygen loss from the lattice in the initial charge and the gradual structural transformation during cycling can lead to a capacity degradation and potential decay for the cathode materials. In this work, Sn 4+ is used to partially substitute Mn 4+ to prepare a series of Li(Li 0.17 Ni 0.25 Mn 0.58-x Sn x )O 2 (x = 0, 0.01, 0.03, and 0.05) samples through a spray-drying method. Structure characterization reveals that the 10 Sn 4+ substituted samples with a suitable amount show a low cation mixing, indicating an enhanced ordered layer structure. Moreover, the metal-oxygen (M-O) covalency is gradually decreased with increasing Sn 4+ amount. It is shown from the initial charge-discharge curves that Sn 4+ substituted samples present a shorter charging potential plateau at 4.5 V (vs Li/Li + ), implying that oxidation of the O 2ion to O 2 is suppressed by Sn 4+ substitution and lead to the minor structural change. Among the Sn 4+ substituted 15 samples, the Li(Li 0.17 Ni 0.25 Mn 0.55 Sn 0.03 )O 2 sample exhibits a higher capacity retation of 86% after 400 cycles at 0.1 C rate and 92 % after 200 cycles at 1 C rate, showing an excellent cycle stability and highrate capability as compared with the as-prepared sample. The electrochemical performance improvement can be attributed to the influence of Sn such as enlarging Li ion diffusion channel due to large ionic radius of Sn 4+ substitution with respect to Mn 4+ , higher bonding energy of Sn-O than Mn-O, and weakening M-20 O covalency. All the influence is favorable for stabilization of the host lattice in Li-rich layered oxides. 65 the lithium ion diffusion channel and decrease the M-O covalency in Li-rich layered oxides. Correspondingly, the oxygen

Study of Cathode Materials for Lithium-Ion Batteries: Recent Progress and New Challenges

“…This result demonstrates that Mg doping only slows the initial activation process of the monoclinic Li 2 MnO 3 component with the higher amount of dopant (x = 0.05). This is in agreement with the result reported in the literature for the partial substitution of Mn by Sn [67]. The partial substitution of Mn by Mg suppresses the capacity resulting from the activation of Li 2 MnO 3 .…”

Tuning Anionic Redox Activity and Reversibility for a High‐Capacity Li‐Rich Mn‐Based Oxide Cathode via an Integrated Strategy

“…However, the peaks of 3% LSO and 5% LSO clearly show a shift to higher angle, which indicates a decrease of the interplanar spacing of the 003 crystal plane. This phenomenon may be caused by the dissolution of Li + out of the bulk phase from the uneven coating layer during the high‐temperature synchronous lithiation reaction,[16b] which is confirmed by elemental mapping images obtained by transmission electron microscopy (TEM) (see below).…”

“…Compared with the pristine material, the 003 peak of 1% LSO shifts to a lower 2θ angle, which indicates that the 003 slabs have expanded due to the doping and migration of Sn 4+ during the coating process. [12e,16] This expansion is beneficial to the lithium insertion/extraction process. However, the peaks of 3% LSO and 5% LSO clearly show a shift to higher angle, which indicates a decrease of the interplanar spacing of the 003 crystal plane.…”

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

“…For example, Gao et al . substituted Sn 4+ for Mn 4+ and reported on improved electrochemical performance of Li 1.17 Ni 0.25 Mn 0.55 Sn 0.03 O 2 over Li 1.17 Ni 0.25 Mn 0.58 O 2 . Aurbach et al .…”