Electrochemical investigations of the LiNi0.45M0.10Mn1.45O4 (M=Fe, Co, Cr) 5V cathode materials for lithium ion batteries

Influence of annealing temperature on the electrochemical and surface properties of the 5-V spinel cathode material LiCr0.2Ni0.4Mn1.4O4 synthesized by a sol–gel technique

“…4.9 V representing an activity other than reduction of Mn and Ni. This signal was previously reported as Cr 4+ /Cr 3+ reduction [17] indicating that Cr is an electrochemically active element in the synthesized spinel samples.…”

“…/Ni 4+ activities, respectively [21]. Additionally, there is a shoulder close to 5 V in CVs of the samples annealed at 900 and 1,000°C, which is possibly an indication of Cr 3+ /Cr 4+ activity [17]. In fact, in the reduction sweep of all materials, there is a signal at ca.…”

“…3d) for the powders synthesized at 800, 900, and 1,000°C. This is commonly observed in rate capability tests of cathode materials [17] [20]. However, for the powders synthesized at lower temperatures, 600 and 700°C, the results from rate capability experiments are not straightforward; the capacity retention increases from C/2 to C and from C to 2C for 600 and 700°C powders, respectively.…”

“…It has been shown that cationic substitutions could eliminate formation of the Li y Ni 1−y O impurity phase and stabilize the disordered spinel structure, which has superior rate properties compared to the ordered one [14]. So far, several elements like Al [15], Fe [16,17], Co [16][17][18][19], Cr [12,15,17,[19][20][21][22][23][24], Cu [25], Ti [26][27][28], Ru [29], Mg [16,30], Zn [16], W [31], and Zr [15] have been examined for this purpose. Among these elements, the addition of Cr has been shown to be more successful than the others to increase cell performance [15,17].…”

“…So far, several elements like Al [15], Fe [16,17], Co [16][17][18][19], Cr [12,15,17,[19][20][21][22][23][24], Cu [25], Ti [26][27][28], Ru [29], Mg [16,30], Zn [16], W [31], and Zr [15] have been examined for this purpose. Among these elements, the addition of Cr has been shown to be more successful than the others to increase cell performance [15,17]. The electrochemical activity will increase to 4.9 V where the Cr 3+ /Cr 4+ redox couple occur [11,12] [10,21,22,[34][35][36][37].…”