How does the thermal decomposition temperature of sodium-ion battery cathodes affect safety?

正极热分解温度是电芯热失控临界安全底线，数值越高耐高温、抗滥用能力越强。高温、过充、针刺短路时，正极分解会释放活性氧引燃电解液，触发连锁放热起火爆炸。聚阴离子分解温度超 500℃，几乎不释氧，适合工商业大容量储能；普鲁士蓝仅 250-300℃，高温失水碎裂产气多；层状氧化物分解温度中等，高压下易释氧存在安全隐患。夏季户外储能、大功率快充持续发热环境中，低分解温度正极会加速电解液水解，造成电芯胀气鼓包。电芯安全设计优先选用高热稳定正极，搭配阻燃电解液、隔热隔膜双重防护，降低热失控概率，同时产品必须通过 UN38.3、挤压、针刺等强制安全检测才能流通使用。

The thermal decomposition temperature of cathodes serves as the critical safety threshold against thermal runaway; higher values mean superior high-temperature and abuse resistance. Under high temperature, overcharge or nail penetration, decomposed cathodes release active oxygen that ignites electrolytes and triggers chain exothermic combustion. Polyanions decompose above 500°C with negligible oxygen release for industrial large-scale energy storage. Prussian blue decomposes at 250–300°C, losing crystal water and generating massive gas at high temperatures. Layered oxides have moderate decomposition temperatures but release oxygen under high voltage with hidden risks. Cathodes with low decomposition temperatures accelerate electrolyte hydrolysis and cell swelling in summer outdoor energy storage and high-rate charging. Cell safety design prioritizes thermally stable cathodes paired with flame-retardant electrolytes and heat-resistant separators to lower thermal runaway risks, and all products must pass mandatory safety tests including UN38.3, extrusion and nail penetration for market access.