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Lithium-ion batteries suffer severe power loss at temperatures below zero degrees Celsius, limiting their use in applications such as electric cars in cold climates and high-altitude drones. The practical consequences of such power loss are the need for larger, more expensive battery packs to perform engine cold cranking, slow charging in cold weather, restricted regenerative braking, and reduction of vehicle cruise range by as much as 40 per cent. Previous attempts to improve the low-temperature performance of lithium-ion batteries have focused on developing additives to improve the low-temperature behaviour of electrolytes, and on externally heating and insulating the cells. Here we report a lithium-ion battery structure, the 'all-climate battery' cell, that heats itself up from below zero degrees Celsius without requiring external heating devices or electrolyte additives. The self-heating mechanism creates an electrochemical interface that is favourable for high discharge/charge power. We show that the internal warm-up of such a cell to zero degrees Celsius occurs within 20 seconds at minus 20 degrees Celsius and within 30 seconds at minus 30 degrees Celsius, consuming only 3.8 per cent and 5.5 per cent of cell capacity, respectively. The self-heated all-climate battery cell yields a discharge/regeneration power of 1,061/1,425 watts per kilogram at a 50 per cent state of charge and at minus 30 degrees Celsius, delivering 6.4-12.3 times the power of state-of-the-art lithium-ion cells. We expect the all-climate battery to enable engine stop-start technology capable of saving 5-10 per cent of the fuel for 80 million new vehicles manufactured every year. Given that only a small fraction of the battery energy is used for self-heating, we envisage that the all-climate battery cell may also prove useful for plug-in electric vehicles, robotics and space exploration applications.

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Fast charging is a key enabler of mainstream adoption of electric vehicles (EVs). None of today's EVs can withstand fast charging in cold or even cool temperatures due to the risk of lithium plating. Efforts to enable fast charging are hampered by the trade-off nature of a lithium-ion battery: Improving low-temperature fast charging capability usually comes with sacrificing cell durability. Here, we present a controllable cell structure to break this trade-off and enable lithium plating-free (LPF) fast charging. Further, the LPF cell gives rise to a unified charging practice independent of ambient temperature, offering a platform for the development of battery materials without temperature restrictions. We demonstrate a 9.5 Ah 170 Wh/kg LPF cell that can be charged to 80% state of charge in 15 min even at -50 °C (beyond cell operation limit). Further, the LPF cell sustains 4,500 cycles of 3.5-C charging in 0 °C with <20% capacity loss, which is a 90× boost of life compared with a baseline conventional cell, and equivalent to >12 y and >280,000 miles of EV lifetime under this extreme usage condition, i.e., 3.5-C or 15-min fast charging at freezing temperatures.

Temperature is critical to the performance, durability and safety of Li-ion batteries. This paper reports in situ measurement of the radial temperature distribution inside a cylindrical Li-ion battery cell. 18650-size cylindrical cells with multiple micro thermocouples embedded are designed and manufactured. The radial temperature distribution is obtained under various operating conditions. The effects of critical parameters, such as discharge C rate, ambient temperature, and cooling condition, are investigated. It is found that higher discharge C rate and lower ambient temperature lead to higher temperature rise and larger temperature gradient within the battery cell. Stronger cooling results in smaller temperature rise but larger temperature gradient. Correlation between relative temperature gradient and cooling coefficient suggests that the assumption of uniform temperature distribution is applicable under natural-convection conditions but not applicable under strong forced convection conditions. The present results provide valuable experimental data that can be readily used to validate electrochemical-thermal coupled (ECT) battery models.Driven by the ever-increasing applications in electric vehicles and grand challenges, 1-4 the need for Li-ion batteries with enhanced performance, durability and safety is increasing. Previous studies show that temperature is critical to the performance, durability and safety of Li-ion batteries. 5-25 On one hand, the performance is reduced at lower temperatures, 6-11 and too low temperature can even cause detrimental lithium plating during charge. 12-14 On the other hand, a Li-ion battery degrades considerably faster at higher temperatures, 15-19 and excessively high temperature can lead to breakdown of the solid electrolyte interface (SEI) layer, 20-22 electrolyte decomposition, 23-25 and even to disastrous thermal runaway. 2,26,27 The surface temperatures of Li-ion cells, batteries and battery packs are commonly monitored. 28,29 However, surface temperature is expected to be different from internal temperature due to the very low thermal conductivity (∼1 W m −1 K −1 ) of electrodes and separator in the through plane direction. 5,30-32 This spatial temperature distribution inside a Li-ion battery may exacerbate the non-uniform distribution of current density 33-35 due to complex interactions among local reaction current, state of charge (SOC) and temperature. Under extreme conditions, e.g. accidental short circuit or overcharge, substantial heat is generated internally and monitoring of surface temperature could significantly underestimate the maximum temperature. Measuring internal temperature can thus provide more accurate information and is a better indicator of the health and safety of a Li-ion battery.In addition, electrochemical-thermal coupled (ECT) modeling has been widely used in the research and development of Li-ion batteries to gain insight into internal processes, to optimize battery design and operation, as well as to improve performance, durability and safety...