Carbonated Beverage Chemistry for High‐Voltage Battery Cathodes

Advanced lithium-ion batteries utilize high upper cut-off voltages up to 4.8 V versus lithium metal to reach extraordinary energy densities. Such a harsh environment challenges the cathode stability and requires the construction of robust cathode electrolyte interphases at their electrochemical interface. Inspired by carbonated beverages with supersaturated CO₂, here, a surface modification strategy that produces effective passivation layer of low modulus from the weakest link, is proposed CO₂ bubbles preferentially nucleate and grow at rough surfaces, which in oxide cathodes, are also the local regions offering fast degradation pathway. Metal ion exchange on carbonated layer assists the construction of highly elastic interface under the guidance of packing factor. This method enables surface reconstruction at both primary and secondary particle levels for various cathodes exemplified by high-voltage LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) and LiCoO₂ (LCO). Remarkably, with ultra-high upper cut-off voltage of 4.8 V versus Li⁺/Li, over 235 mAh g^-1 discharge capacity, and over 900 W h kg^-1 discharge energy at cathode level, ≈90% capacity retention can be obtained for LiNi_0.8Co_0.1Mn_0.1O₂ over 100 cycles at 0.5 C with commercial carbonate electrolytes. This carbonated beverage chemistry is promising for constructing high-quality surface passivation in many extreme-condition applications beyond battery cathodes.