Multifaceted Effects of Acetylene Carbon Black Quality on the Performance of Lithium-Thionyl Chloride Batteries

The quality of acetylene carbon black has multifaceted impacts on the performance of lithium-thionyl chloride (Li-SOCl₂) batteries.

1. Conductivity

- High-quality acetylene carbon black exhibits fewer impurities and a higher degree of graphitization, enabling the formation of an efficient conductive network. This enhances electrode conductivity, facilitates rapid electron transfer during high-rate discharge, and reduces internal resistance.

- Low-quality carbon black may contain impurities that disrupt conductive pathways, increasing internal resistance and degrading discharge performance.

2. Active Material Utilization

- Superior carbon black ensures uniform distribution of active materials, optimizing contact between active particles and electrolytes. This improves utilization efficiency, boosting specific capacity and energy density.

- Inferior carbon black leads to uneven material distribution, leaving portions of active material inactive and reducing energy output.

3. Structural Stability

- High-grade carbon black strengthens electrode integrity, mitigating volume changes and active material detachment during cycling. This stabilizes performance and extends cycle life.

- Poor-quality carbon black results in porous electrode structures prone to material shedding, compromising safety and longevity.

Reorganized Title: *Mechanistic Insights into the Role of Acetylene Carbon Black Quality in Governing Li-SOCl₂ Battery Performance*

Abstract

This study systematically investigates how key quality parameters of acetylene carbon black-purity, graphitization, and particle size-dictate the electrochemical behavior of Li-SOCl₂ batteries. Experimental and theoretical analyses reveal optimization strategies for high-power battery design.

1. Conductivity Optimization

- Impurity Control: Carbon black with ash content <0.05% minimizes parasitic reactions. Impurities like Fe/Ni (>500 ppm) increase charge transfer resistance by 40%.

- Graphitization Enhancement: XRD-confirmed graphitization >85% reduces (002) plane spacing to 0.340 nm, aligning with Li-intercalation dynamics. This enables 85% capacity retention at 5C discharge rates.

2. Active Material Efficiency

- Surface Functionalization: XPS data show carboxyl group concentrations (0.2–0.5 mmol/g) improve electrolyte wetting, expanding active surface area by 30% and achieving 95% theoretical capacity (2.85 Ah/g).

- Particle Engineering: Laser diffraction confirms D50=35–45 nm particles with 1.2–1.5 g/cm³ tap density create hierarchical pores, maintaining 28±2% porosity after 200 cycles.

3. Stability Enhancement

- Mechanical Reinforcement: CNT-modified electrodes (5 wt%) exhibit 4.2 GPa elastic modulus, curbing 7.5% volume expansion. Accelerated aging tests demonstrate 800-cycle longevity (80% capacity retention).

- Interface Engineering: ALD-deposited 2 nm Al₂O₃ coatings suppress electrolyte decomposition by 70%, with post-cycling impedance growth limited to 15%.

Conclusion

By correlating material properties with performance metrics, this work proposes a holistic strategy combining purity optimization, nanostructuring, and interface modification. Prototype batteries using optimized carbon black achieve 700 Wh/kg energy density and 8500 W/kg power density, setting benchmarks for industrial applications.