Ti surface doping of LiNi_0.5Mn_1.5O_4−δ positive electrodes for lithium ion batteries

Abstract

LiNi0.5Mn1.5O4−δ surface is doped with Ti ion maintaining the spinel structure at 500 °C, higher annealing temperatures cause Ti diffusion from surface towards the core.

Synthesis of LiNi0.5Mn1.5O4 via Ammonia‐free Co‐precipitation Method: Insight in the Effects of the Lithium Additions on the Morphology, Structure and Electrochemical properties

“…It is difficult for us to judge that the obtained LiNi 0.5 Mn 1.5 O 4 cathode materials belong to ordered P4 3 32 or disordered Fd‐3m phase only by XRD. No superstructure peaks around 15.3 ° implies the existing disorder at the (Mn, Ni) site, or at most, only partial order ,. As reported,,, it can be observed some small impurity of the rock salt phase like Li x Ni 1‐x O 2 ,Ni x O and Li x Ni y Mn z O 2 etc.…”

“…As well known, both the morphology and structure of the cathode materials are the main important factors influencing the electrochemical performance. A plenty of strategies such as surface coating, doping, synthesis routine and calcination process etc. have been adopted by researchers to obtain superior electrochemical properties.…”

Study on synthesis of spinel LiNi 0 . 5 Mn 1 . 5 O 4 cathode material and its electrochemical properties by two‐stage roasting

“…[46][47][48] In addition, the spinel LNMO has a high working voltage of about 4.7 V, and has the advantages of good cycling stability, simple preparation, low cost, stable structure, good safety performance, and so on. [49][50][51][52][53] At present, the preparation methods of LNMO cathode materials include high-temperature solid-phase process, sol-gel process, coprecipitation process, hydrothermal synthesis process, combustion process, molten salt process, spray pyrolysis process, ultrasonic chemical synthesis process, and so on. Each of the above processes has its own advantages and disadvantages.…”

“…The specific energy of spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) is high, the theoretical value is about 1100 Wh kg −1 , and the actual value can reach 700 Wh kg −1 46‐48 . In addition, the spinel LNMO has a high working voltage of about 4.7 V, and has the advantages of good cycling stability, simple preparation, low cost, stable structure, good safety performance, and so on 49‐53 …”

Role of Al-doping with different sites upon the structure and electrochemical performance of spherical LiNi0.5Mn1.5O4 cathode materials for lithium-ion batteries

“…37 Metal elements with a similar ionic radius have been utilized to occupy some transition metal ion sites in the form of single or dual doping: Cr, Fe, Co, Ga, Cu, Zn, Mg, and Ti. [38][39][40][41] Some elements with a larger ionic radius, such as Zr, Ru, Y, Ce, Nd and Sm, [42][43][44][45][46] have been introduced into LNMO to reinforce the stability of the structure and performance. Zhang et al 47 studied Cr-doped LNMO cathode materials from low to high temperature prepared by a sol-gel method and calcination at 900 C. Al, with its smaller ionic radius, can diffuse readily into the crystal structures of LNMO, and exibly affects the states of Ni and Mn when doped at different sites.…”