Influence of the Mixing and Synthesis Conditions of the Precursors of the NMC811 cathodes on their Electrochemical Performance

PARA, M. LAURA; QUERIO, ANDRE; ALIDOOST, M.; SHIEA, MOHSEN; BUFFO, ANTONIO; BOCCARDO, GIUANLUCA; BODOARDO, SILVIA; MARCHISIO, DANIELE

Congreso; 72nd Annual Meeting of the International Society of Electrochemistry; 2021

Electrochemical energy storage technologies are key for the complete energy transition and the successful use of renewable energy sources, especially for mobile devices, transport sector, and stationary storage.Since the traditional cathode of LiCoO2 release up to today, lithium ion batteries, dominate de market and are widely spread in a great variety of devices.An alternative material that reduce the Co content and decrease the high costs and toxicity associated with it, are the Ni-rich layered transition metal oxides cathodes (LiNi1-x-yMnxCoyO2), as NMC532, NMC622, NMC811. These materials are expected to increase its uses in the next years, hence more information is needed regarding its production[1].These cathodes can be obtained by calcining the precursor Ni1-x-yMnxCoy(OH)2 (NMC hydroxide) with LiOH. The synthesis of the transition metals hydroxide through coprecipitation is an economical and scalable method, it is also commonly used a complexing agent in its production. Although, there is needed more information regarding the influences of synthesis conditions to improve the manufacturing.In this work, we focus in a systematic study of the influence of synthesis conditions in the NMC hydroxides via coprecipitation, studying the effect of mixing on particle characteristics as particle size distribution (PSD), morphology and crystallinity. In addition, different calcination protocols were studied to obtain the NMC oxide. Finally, it was also investigated the relationship between the NMC hydroxide characteristics in the corresponding oxide electrochemical performance.The NMC hydroxides were synthesized through a coprecipitation process, to ensure a precise control in the reactants solutions mixing, a multi-inlet vortex mixer (Figure 1) was used [2]. All experiments were performed with a fixed ratio off Ni:Mn:Co = 8:1:1, testing different flow rates, different ratio between the total metal concentration, ratio of complexing agent (NH4OH) and reactant concentration. The resulting particles (NMC hydroxides, Figure 2) were characterized to determine the tap density, PSD and morphology, using DLS and SEM. Finally, it was optimized the calcination protocol, under air flow, to obtain LiNi0.8Mn0.1Co0.1O2 (Figure 3) from the precursors. The active materials were electrochemically characterized by charge-discharge galvanostatic cycling, CV, EIS in coin cells.