Impact of precursor characteristics on the structural and electrochemical performance of spinel LiNi0.5Mn1.5O4 cathode materials

Le résumé fourni par la source

The spinel lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O 4 , LNMO) has been paid wide attraction due to the features such as cobalt-free, environmental friendliness, high operating voltage and high energy density in material level. The precursor plays the key role in pursuing such goal. In this paper, LNMO was synthesized by co-precipitation method using two types of precursors (main differences were particle size and surface morphology). The discharge specific capacity of S-LNMO (prepared using smaller-size precursor) can reach high up to 139 mAh g −1 (1 C = 150 mA g −1 ), with a retention of 92.2 % after 100 cycles. After carefully characterized employing XRD, SEM, BET, in situ XRD and XPS, the origins of better electrochemical performance for S-LNMO could be summarized as follows: firstly, the precursor does not change the crystal structure of the LNMO material. Secondly, a ‘fusion phenomenon’ is observed during charging/discharging cycles in both LNMO materials, but the surface morphological evolutions are various with each other. Thirdly, S-LNMO sample with higher crystallinity and fewer structural defects suffer less from the respiratory effect during long-term lithiation/de-lithiation process. Fourthly, less amount of Mn 3+ diminished the consequence of structural distortion during electrochemical reaction. In addition, the full battery further demonstrates that the structure of the S-LNMO material is more stable. These results provide insights for the design of advanced high-performance cathode materials for lithium-ion batteries.

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