Li[Ni_0.5Mn_0.3Co_0.2]O₂ as a Superior Alternative to LiFePO₄ for Long-Lived Low Voltage Li-Ion Cells

Abstract

Single crystal Li[Ni0.5Mn0.3CoO.2]O2//graphite (NMC532) pouch cells with only sufficient graphite for operation to 3.80 V (rather than ≥4.2 V) were cycled up to either 3.65 or 3.80 V to facilitate comparison with LiFePO4//graphite (LFP) pouch cells on the grounds of similar maximum charging potential and similar negative electrode utilization. The NMC532 cells, when constructed with only sufficient graphite to be charged to 3.80 V, have an energy density that exceeds that of the LFP cells and a cycle-life that greatly exceeds that of the LFP cells at 40, 55, and 70°C. Excellent lifetime at high temperature is demonstrated with electrolytes that contain lithium bis(fluorosulfonyl)imide (LiFSI) salt, well beyond those provided by conventional LiPF6 electrolytes. Ultra-high precision coulometry and electrochemical impedance spectroscopy are used to complement cycling results and investigate the reasons for the improved performance of the NMC cells. NMC cells, particularly those balanced and charged to 3.8 V, show better coulombic efficiency, less capacity fade and higher energy density compared to LFP cells and are projected to yield lifetimes approaching a century at 25°C.

Gap Analysis in Eco Categories, Electric Vehicle Comparison and Solutions to Global Transport Challenges

“…There are already breakthroughs in the field. The NMC532 lithium battery cell has been projected to have 100 years of lifetime for 20 °C work temperature [18]. The real lifetime is expected to be lower, but this is amazing achievement considering that the current lithium battery technology allows 15 years of calendar lifetime.…”

Problems and Opportunities for Cost-Effective Photovoltaic Systems for Private Use

“…There are already breakthroughs in the field. The NMC532 Li battery cell have been projected to have 100 years of lifetime for 20°C work temperature, [6]. The real lifetime is expected to be lower, but this is amazing achievement considering that the current Li battery technology allows 15 years of calendar lifetime.…”

“…The real lifetime is expected to be lower, but this is amazing achievement considering that the current Li battery technology allows 15 years of calendar lifetime. At the same time the NMC532 Li battery cell shows no sudden failure and no signs of capacity loss after nearly 2000 cycles, [6]. The near future is expected to offer Li batteries with high calendar and cycle lives, which will allow cheaper electric vehicles and PV systems to be designed, that may not require battery change for their lifetime.…”

Fabrication of a LiNi0.5Mn0.4Ti0.03Mg0.03Nb0.01Mo0.03O2 cathode for low-cost long-life lithium-ion batteries

“…Recent work suggests that NCM523 holds great promise as an alternative to the super stable LiFePO 4 cathode for applications in ultra-long-life LIBs. 8 So far, medium-Ni cathodes such as NCM523 and NCM622 are still projected to hold the largest share of global ternary cathode production in the next decade, owing to their merits of high thermal stability, long cycle life, and low manufacturing cost despite the high concentration of the undesired Co. 9 In this context, the elimination of Co in low-to-medium-Ni layered cathodes without sacrificing their performance is highly attractive; however, it is a challenging scientific task because the Co contents in these cathodes are high (Z 20%). A common strategy is to directly substitute Co with a much cheaper but electrochemically inactive element, such as Mn.…”

“…Recent work suggests that NCM523 holds great promise as an alternative to the super stable LiFePO 4 cathode for applications in ultra-long-life LIBs. 8 So far, medium-Ni cathodes such as NCM523 and NCM622 are still projected to hold the largest share of global ternary cathode production in the next decade, owing to their merits of high thermal stability, long cycle life, and low manufacturing cost despite the high concentration of the undesired Co. 9…”