The Effect of Silicon Grade and Electrode Architecture on the Performance of Advanced Anodes for Next Generation Lithium-Ion Cells

Abstract

To increase the specific capacity of anodes for lithium-ion cells, advanced active materials, such as silicon, can be utilized. Silicon has an order of magnitude higher specific capacity compared to the state-of-the-art anode material graphite; therefore, it is a promising candidate to achieve this target. In this study, different types of silicon nanopowders were introduced as active material for the manufacturing of composite silicon/graphite electrodes. The materials were selected from different suppliers providing different grades of purity and different grain sizes. The slurry preparation, including binder, additives, and active material, was established using a ball milling device and coating was performed via tape casting on a thin copper current collector foil. Composite electrodes with an areal capacity of approximately 1.70 mAh/cm² were deposited. Reference electrodes without silicon were prepared in the same manner, and they showed slightly lower areal capacities. High repetition rate, ultrafast laser ablation was applied to these high-power electrodes in order to introduce line structures with a periodicity of 200 µm. The electrochemical performance of the anodes was evaluated as rate capability and operational lifetime measurements including pouch cells with NMC 622 as counter electrodes. For the silicon/graphite composite electrodes with the best performance, up to 200 full cycles at a C-rate of 1C were achieved until end of life was reached at 80% relative capacity. Additionally, electrochemical impedance spectroscopies were conducted as a function of state of health to correlate the used silicon grade with solid electrolyte interface (SEI) formation and charge transfer resistance values.

Gaining a New Technological Readiness Level for Laser-Structured Electrodes in High-Capacity Lithium-Ion Pouch Cells

“…At C-rates of 2C and 3C, a 10% increase in relative capacity can be achieved compared to the reference cells. This can be related to a reduced tortuosity, ohmic polarization, and overpotential of the cells with structured electrodes, as it has been described in [12,15,17,18,20].…”

Gaining a New Technological Readiness Level for Laser-Structured Electrodes in High-Capacity Lithium-Ion Pouch Cells

“…At C-rates of 2C and 3C, a 10% increase in relative capacity can be achieved compared to the reference cells. This can be related to a reduced tortuosity, ohmic polarization, and overpotential of the cells with structured electrodes, as it has been described in [12,15,17,18,20].…”

Review on Recent Progress and Challenges in Laser‐Structuring of Electrodes for Lithium‐Ion Batteries

“…Meyer et al ablated line structures into the electrode material. [69] However, it was found that the degradation mechanisms were still inhibiting the performance. Performance and lifetime of pure graphite electrodes were better than the Si/C composites.…”

“…The graphite particles are connected electrically by the silicon and the carbon black. [ 69 ] These characteristics lead to an increased durability of the material as it facilitates the volume change with minimal damage to the electrode. However, as silicon undergoes large volume changes during de‐/lithiation, increasing capacity loss and thickness change with increasing silicon content have been observed.…”

Optimizing Structural Patterns for 3D Electrodes in Lithium-Ion Batteries for Enhanced Fast-Charging Capability and Reduced Lithium Plating

“…The composition of the cathode slurry is summarized in Table 1. The porosity values for anode and cathode were calculated according to the common procedure described in Equation (S2) [38].…”

Gaining a New Technological Readiness Level for Laser-Structured Electrodes in High-Capacity Lithium-Ion Pouch Cells

“…At C-rates of 2C and 3C, a 10% increase in relative capacity can be achieved compared to the reference cells. This can be related to a reduced tortuosity, ohmic polarization, and overpotential of the cells with structured electrodes, as it has been described in [12,15,17,18,20].…”

Review on Recent Progress and Challenges in Laser‐Structuring of Electrodes for Lithium‐Ion Batteries

“…Meyer et al ablated line structures into the electrode material. [69] However, it was found that the degradation mechanisms were still inhibiting the performance. Performance and lifetime of pure graphite electrodes were better than the Si/C composites.…”

“…The graphite particles are connected electrically by the silicon and the carbon black. [ 69 ] These characteristics lead to an increased durability of the material as it facilitates the volume change with minimal damage to the electrode. However, as silicon undergoes large volume changes during de‐/lithiation, increasing capacity loss and thickness change with increasing silicon content have been observed.…”

Optimizing Structural Patterns for 3D Electrodes in Lithium-Ion Batteries for Enhanced Fast-Charging Capability and Reduced Lithium Plating

“…The composition of the cathode slurry is summarized in Table 1. The porosity values for anode and cathode were calculated according to the common procedure described in Equation (S2) [38].…”

Gaining a New Technological Readiness Level for Laser-Structured Electrodes in High-Capacity Lithium-Ion Pouch Cells

“…At C-rates of 2C and 3C, a 10% increase in relative capacity can be achieved compared to the reference cells. This can be related to a reduced tortuosity, ohmic polarization, and overpotential of the cells with structured electrodes, as it has been described in [12,15,17,18,20].…”

Review on Recent Progress and Challenges in Laser‐Structuring of Electrodes for Lithium‐Ion Batteries

“…Meyer et al ablated line structures into the electrode material. [69] However, it was found that the degradation mechanisms were still inhibiting the performance. Performance and lifetime of pure graphite electrodes were better than the Si/C composites.…”

“…The graphite particles are connected electrically by the silicon and the carbon black. [ 69 ] These characteristics lead to an increased durability of the material as it facilitates the volume change with minimal damage to the electrode. However, as silicon undergoes large volume changes during de‐/lithiation, increasing capacity loss and thickness change with increasing silicon content have been observed.…”

Optimizing Structural Patterns for 3D Electrodes in Lithium-Ion Batteries for Enhanced Fast-Charging Capability and Reduced Lithium Plating

“…The composition of the cathode slurry is summarized in Table 1. The porosity values for anode and cathode were calculated according to the common procedure described in Equation (S2) [38].…”