Practical design of NI-Rich LI-ION cathodes for long cycle life in high energy density applications

Lithium-ion batteries are approaching technological maturity, yet the energy density and cycle life of batteries must be improved before widespread electrification can occur. There is often a tradeoff between energy density and cycle life where improving one detracts from the other. This work investigates the impact of binder selection and densification as methods to increase long-term cycling stability in high-energy-density lithium-ion cells. Cathode densification collapses pores and increases particle-particle contact and electrical conductivity (Fig 1). It was determined that binder selection did not impact the maximum achievable cycling stability in cells, but that it did regulate the cathode density at which optimum stability was achieved. Increased stability in properly densified cathodes was attributed to lowered overpotentials during cycling resulting from properly balancing electronic and ionic conductivities.