Ultrahigh Power Density and Safety Induced by Ultrathin Electrode Design and Bi-Salt Electrolyte Tailored Lithium Ion Batteries toward Durable 48 V Start/Stop Application

Itis a bottleneck issue for state-of-the-art start/stop batteriesused in commercialized electrical vehicles to have a long cyclinglife, high power output, and understanding safety performance. Inthis work, we fabricate prismatic cells to unravel how these tradeoffscan be balanced based on the material and cell design. Small-particleLi[Ni1/3Co1/3Mn1/3]O-2 ternarymaterials with surface modification and isotropous graphite are respectivelyemployed as cathode and anode to provide super power density. Ceramic-coatedseparators with high permeability and wide-temperature electrolyteswith high conductivities enable the safety and cold cranking performance.Ultrathin-coating electrodes and whole poles are achieved to shortenthe transferring distance of Li ions and promote the efficiency ofLi intercalation and deintercalation kinetics, which demonstratesthe lower internal resistance and current density. By unlocking chargetransfer limitations, the cell presents a high discharge power densityof >5000 W/kg at 25 & DEG;C, a 50% SOC (state of charge), and excellentcold cranking characteristics at -30 & DEG;C. A capacity retentionof 3 C (100% depth of discharge, DoD) cycling approaches 80% over6800 cycles at 25 & DEG;C and 4300 cycles at 45 & DEG;C. Also, a capacityretention of cycling at room temperature according to worldwide lightvehicle test procedures reaches up to 92.3% over 6000 cycles withthe energy throughput of 614.5 kWh and direct charge internal resistancedoes not soar with the cycling ongoing. The mechanism of the capacityloss is dissolved Ni, Co, and Mn, which results in irreversible lossof Li. The cell shows high safety characteristics by passing the 3C overcharge and nail penetration tests. It is evident that the reportedcell can be a promising commercialized candidate for 48 V start/stopand hybrid electric vehicle solutions.