Spray printing and optimization of anodes and cathodes for high performance Li-Ion batteries

A spray printing manufacturing approach to lithium-ion batteries was investigated with a focus on minimizing inactive fractions and maximizing energy and power densities of printable electrodes. Using a lithium titanate based anode initially and comparing with conventional electrodes, the effects of conductivity enhancer and binder fractions, post-calendaring effects, different electrode manufacturing methods, conductivity enhancer types and electrode thicknesses were explored, and optimum electrode structures were identified. These insights were then applied to a lithium iron phosphate based cathode, and full spray printed lithium titanate/lithium iron phosphate cell configurations were investigated. Notably, the full-cell battery with a 1:1 capacity ratio of lithium titanate to lithium iron phosphate had a stable specific energy density of ∼300 Wh/kg and a power density of ∼2500 W/kg, showing the promise of layer-by-layer spray printing to realize fully the intrinsic properties of electrode materials in lithium-ion battery cells. Electrochemical behavior of layer-by-layer spray printed electrodes was investigated based on lithium titanate anodes and lithium iron phosphate cathodes to quantify the best structural functionalities and combinations and then to establish basic design rules of printable electrode systems. The parameters investigated were: (1) minimizing inactive fractions; (2) quantifying the calendaring effect; (3) comparative performances of identical spray printed and slurry cast electrodes; (4) optimizing the conductivity enhancers; (5) investigating electrode thickness-dependent properties; and (6) balancing LTO:LFP capacities in full-cell battery systems. [Display omitted]