Synergizing mimetic Debye-screening effect and robust interphase engineering for long-life low-temperature lithium-ion batteries

The reliable operation of lithium-ion batteries (LIBs) in low temperatures has long been hindered by severe side reactions on graphite anodes. To develop a commercially viable low-temperature electrolyte, we design a solvent-resistant Nitrate-coordinated electrolyte. The practical Ah-level graphite‖LiNi0.5Co0.2Mn0.3O2 pouch cell with the newly developed electrolyte demonstrates a significant breakthrough in cycling stability, exhibiting negligible capacity fade after 250 cycles at −30 °C and 0.1 C. NO3−, as the functional additive, compresses the electric field around Li+ through electrostatic interactions, mimicking the Debye-screening effect and inducing the coordinative exclusion of free ethyl acetate molecules at low temperatures. The transformation from contact ion pairs (CIPs) formed by PF6− to solvent-separated ion pairs is significantly restrained, which mitigates the continuous reactions between the electrolyte and inevitable lithium deposition at low temperature. Additionally, this customized inert CIPs form a solid electrolyte interphase on graphite that exhibits remarkable ionic conductivity and rigidity, preventing excessive Li dendrite growth. This finding offers new insights into the relationship of microstructure-performance for low-temperature electrolytes, demonstrating that relying solely on inert CIPs can also inhibit the decomposition of the interfacial electrolyte, and inspires a unique design concept for high-performance, commercially viable LIBs that operate reliably in sub-zero environments.