Enhancement of LiNi_0.5Mn_1.5O₄ Cathode Materials through Interfacial Modification of Amorphous Al₂O₃ in Lithium Ion Batteries

Abstract

Metal oxide modification can improve the electrochemical stability of cathodes and the cycle-life and rate capacity of rechargeable lithium ion batteries. Spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) has been considered as a promising cathode material for its high operating potential and high energy density. In this work, amorphous nano-Al 2 O 3 with different thicknesses were applied to modify the surface of LNMO. Results of structure and surface analysis showed that the nano-Al 2 O 3 film uniformly distributed on the surface of LNMO material without changing the crystal structure of the material. The electrochemical performances revealed that the capacity decay of bare LNMO materials focused on the first 50 cycles under room and elevated temperatures. It is essential to enhance the electrochemical performances of first 50 cycles. The capacity retention of the first 50 cycles was enhanced by the man made Al 2 O 3 interface between active LNMO and electrolyte. The as-prepared surface modified LNMO material with the amount of Al 2 O 3 at 1.77% exhibited superior rate and cycling performances under the room temperature even at elevated temperature. It also showed that the interfacial effect mechanism on the enhancement of LNMO performances is significantly important during the initial charging process (0%-20% SOC). In contrast to the impedance increasing with the SOC in the bare LNMO batteries, the resistance decreased dramatically in the first 20% SOC and almost kept constant during the following charging process. Both of the interface resistance between the cathode and electrolyte and charge transfer impedance were reduced, and the diffusion rate of lithium ion were improved.

Developing a Double Protection Strategy for High-Performance Spinel LiNi0.5Mn1.5O4 Cathodes

“…4,5 HF can not only attack LiNi 0.5 Mn 1.5 O 4 , resulting in the dissolution of transition metals, but also challenge the stability of a cathode/electrolyte interphase (CEI) by leaching out inorganic components. 6 The electrolyte decomposes on the newly exposed surface of LiNi 0.5 Mn 1.5 O 4 , and the CEI becomes progressively thicker to hinder the electrode reactions. Because HF is inevitably generated by the hydrolysis reaction of LiPF 6 and electrolyte decomposition, 3 it is necessary to pay special attention to suppress the corrosion of HF in high-voltage LiNi 0.5 Mn 1.5 O 4 batteries.…”

Enabling a High-Throughput Characterization of Microscale Interfaces within Coated Cathode Particles

“…The substitution of Ni 2+ for the Mn 4+ sites in the LNMO spinel lattice provides access to the Ni 2+ /Ni 3+ and Ni 3+ /Ni 4+ redox couple at ∼4.7 V (vs Li/Li + ), which allows for an increased range of power. Access to a larger potential window often comes at an expense of a fade in capacity. , This fade in capacity has been attributed in part to adverse side reactions that can occur between the cathode materials and the electrolyte, as well as detrimental surface reconstructions at these relatively high working voltages. , Modifications to the LNMO cathode particle through surface coatings have, therefore, been proposed to improve the stability and performance of these materials. − These surface coatings can assist in preserving the desired performance of the LIB through stabilization of the cathode particle microstructure and improved protection against chemical degradation of the cathode surfaces. Enabling an efficient, high-throughput characterization of the interface between these coatings and the cathode particle will enable improvements to the design of methods used to prepare and tune the properties of the cathode coatings.…”

“…6,7 This fade in capacity has been attributed in part to adverse side reactions that can occur between the cathode materials and the electrolyte, as well as detrimental surface reconstructions at these relatively high working voltages. 8,9 Modifications to the LNMO cathode particle through surface coatings have, therefore, been proposed to improve the stability and performance of these materials. 10−12 These surface coatings can assist in preserving the desired performance of the LIB through stabilization of the cathode particle microstructure and improved protection against chemical degradation of the cathode surfaces.…”

Effect of Presintering Atmosphere on Structure and Electrochemical Properties of LiNi0.5Mn1.5O4 Cathode Materials for Lithium‐Ion Batteries

“…Various methods, such as solid‐state reaction, co‐precipitation, hydrothermal and sol‐gel, have been developed for the preparation of LNMO materials. Solid‐state reaction is generally recognized as a simple and low‐cost process to prepare LNMO materials.…”

“…All these characteristics make LNMO material show great advantages in all aspects. [13] Various methods, such as solid-state reaction, [14][15][16] coprecipitation, [17][18][19] hydrothermal [20,21] and sol-gel, [22,23] have been developed for the preparation of LNMO materials. Solid-state reaction is generally recognized as a simple and low-cost process to prepare LNMO materials.…”