Researchers Unveil Paper On New Battery That Could Last 100 Years
An anonymous reader quotes a report from Electrek: Tesla's advanced battery research group in Canada in partnership with Dalhousie University has released a new paper on a new nickel-based battery that could last 100 years while still favorably comparing to LFP cells on charging and energy density. [...] The paper describes a nickel-based battery chemistry meant to compete with LFP battery cells on longevity while retaining the properties that people like in nickel-based batteries, like higher energy density, which enables longer range with fewer batteries for electric vehicles. The group wrote in the paper's abstract: "Single crystal Li[Ni0.5Mn0.3Co0.2]O2//graphite (NMC532) pouch cells with only sufficient graphite for operation to 3.80 V (rather than [greater than or equal to] 4.2 V) were cycled with charging to either 3.65 V or 3.80 V to facilitate comparison with LiFePO4//graphite (LFP) pouch cells on the grounds of similar maximum charging potential and similar negative electrode utilization. The NMC532 cells, when constructed with only sufficient graphite to be charged to 3.80 V, have an energy density that exceeds that of the LFP cells and a cycle-life that greatly exceeds that of the LFP cells at 40C, 55C and 70C. Excellent lifetime at high temperature is demonstrated with electrolytes that contain lithium bis(fluorosulfonyl)imide (LiFSI) salt, well beyond those provided by conventional LiPF6 electrolytes." The cells showed an impressive capacity retention over a high number of cycles. The research group even noted that the new cell described in the paper could last a 100 years if the temperature is controlled at 25C: "Ultra-high precision coulometry and electrochemical impedance spectroscopy are used to complement cycling results and investigate the reasons for the improved performance of the NMC cells. NMC cells, particularly those balanced and charged to 3.8 V, show better coulombic efficiency, less capacity fade and higher energy density compared to LFP cells and are projected to yield lifetimes approaching a century at 25C." One of the keys appears to be using an electrolyte with LiFSI lithium salts, and the paper notes that the benefits could also apply to other nickel-based chemistries, including those with no or low cobalt. The paper has been published in the Journal of the Electrochemical Society.
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