Electrode materials are the key to electrochemical energy storage devices like supercapacitors. However, current materials can hardly meet the charge-storage capacity and/or operability requirements of practical scenarios in harsh low-temperature conditions. Here we report the advancement in photothermal-assisted supercapacitors operable at −40 °C using an electrochemically active and photothermal electrode material of commercially available TiN nanocrystals. Bifunctional TiN shows broad light absorption (>98%) in the whole solar spectrum and high photothermal conversion efficiency (62.5%). Even in an open atmospheric environment, the photochemical effect boosts the device with a considerable temperature rise from −36.6 °C to −10.8 °C under 1 solar illumination. Meanwhile, the as-fabricated device exhibits highly stable and reversible charge-storage capability. Its capacitance is enhanced by 38.0% at 5 mV s⁻¹ at −40 °C, achieving 70.9% of the capacitance at 25 °C. The energy density is improved by 81.1% at 140 mW cm⁻² at −40 °C, reaching 59.3% of the capacitance at 25 °C. The route for preparing TiN inks and fabricating screen-printed devices is simple and cheap, which is suitable for industrial mass production. The self-heating integration approach provides a promising strategy for designing new functionalized energy-storage devices with low temperature resistant features.

电极材料是电化学能量存储设备（如超级电容器）的关键。但是，当前的材料在恶劣的低温条件下几乎无法满足实际方案的电荷存储容量和/或可操作性要求。在这里，我们报告了使用可商购获得的TiN纳米晶体的电化学活性和光热电极材料，可在-40°C的光热辅助超级电容器中取得的进步。双功能TiN在整个太阳光谱中显示出广泛的光吸收（> 98％）和高的光热转换效率（62.5％）。即使在开放的大气环境中，光化学效应也可以在1个太阳光照射下将器件的温度从-36.6°C升高到-10.8°C，从而增强器件的性能。同时，所制造的器件具有高度稳定且可逆的电荷存储能力。在5 mV s时，其电容提高了38.0％在-40°C时为^-1，在25°C时达到电容的70.9％。在-40°C下140 mW cm ^-2时，能量密度提高了81.1％，在25°C下达到了电容的59.3％。TiN油墨的制备和丝网印刷设备的制备方法简单，便宜，适合工业化批量生产。自热集成方法为设计具有耐低温特性的新型功能化储能设备提供了一种有前途的策略。