nmc cathode optimial particle size effect tap density

#Nmc cathode optimial particle size effect tap density portable#

8 at different C-rates (0.1C–3C), where the porosity was decreased from 60% to 15% towards the current collector. 9 They simulated a Li 2Mn 2O 4 cathode structure with similar arrangement as ref. Dai and Srinivasan revisited the idea of using such graded electrodes to achieve better energy density. They reported that a 15–33% decrease in ohmic resistance in the liquid phase was possible compared to an overall constant porosity design, which in turn increased the deliverable energy. 8 The porosity was decreased in each layer towards the direction of the current collector. simulated a graded LiCoO 2 cathode, where the porosity profile was divided equally into 5 layers, with constant porosity within each layer. The rationale behind such an electrode design approach includes: (i) allowing larger amount of Li + transport in the liquid phase near the current collector through increased porosity in that region of the electrode, and (ii) increasing the local rate of Li + uptake through the use of small particles with reduced diffusion lengths. 8–13 In this article, performance is defined in terms of the usable energy and/or power density during discharge (lithiation) of the cell. 6Ī promising thick electrode design investigated by researchers is the graded electrode, where porosities and particle sizes are spatially varied to improve cell performance. 6,7 This electrode underutilization can be attributed to Li + depletion in the liquid phase and/or a Li + diffusion gradient in the solid-phase. 1–5 Previous studies have revealed that underutilization of the AM near the current collector (CC) at high C-rates is one of the main reasons for power fade in thick electrodes (≥174 μm). However, as the electrode thickness increases, mass transport limitations in both solid and liquid phase become more important impeding the power delivery. Thick electrodes are attractive for high-energy LIB applications because of their potential capability to store high amounts of Li + with increasing amounts of active materials (AM). In LIB cell designs, there is an inherent trade-off between power and energy density.

#Nmc cathode optimial particle size effect tap density portable#

Introduction The need for the development of secondary lithium-ion batteries (LIBs) with both high power and high energy density is imperative for the advancement of portable devices, electric vehicles (EV), and integrated renewable energy systems. Additionally, the simulations indicate that an improvement of 47.7% in energy density, alongside a marginal increase of 0.6% in power density, can be achieved at 4C by structuring the porosity in the layer next to the separator to be higher than the porosity in the layer next to the current-collector. Simulation results highlight that bi-layer cathodes display higher electrode utilization (solid phase lithiation) next to the current-collector compared to conventional monolayer cathodes with an increase of 39.2% in first discharge capacity at 2C. These parameters are used to develop bi-layer numerical models to understand transport phenomena and to predict cell performance with such graded structures. The microstructural, transport, and kinetic information are obtained through 3D imaging and electrochemical impedance spectroscopy (EIS) techniques. These experimental insights are employed to simulate the benefits of 400 μm thick bi-layer graded cathodes with two different particle sizes and porosities in each layer. Hence, in this work, we focus on the effect of material processing conditions on particle morphology and its subsequent influence on microstructure (porosity and tortuosity), along with the resultant transport (solid-phase diffusivity) and kinetic (reaction rate constant) properties of synthesized single-layer cathodes. The simulation results discussed in previous reports on next-generation graded electrodes do not recognize the effect of material processing conditions on microstructural, transport and kinetic parameters. The prospect of thick graded electrodes for both higher energy and higher-power densities in lithium-ion batteries is investigated.