1分鐘充放電：超高倍率的高容量鈉離子電池復合正極材料問世
瀏覽： 發表時間：2021-09-04 13:36:12
近日，國家工信部在回復全國政協委員《關于在我國大力發展鈉離子電池的提案》時表示，高性價比的鈉離子電池有望成為鋰離子電池的重要補充，尤其是在固定式儲能領域將具有良好發展前景。
有關部門支持促進性能優異、符合條件的鈉離子電池在新能源電站、交通工具、通信基站等領域加快應用，推動鈉離子電池全面商業化。
鈉創新能源是我國鈉離子電池技術創新創業的先鋒。開發出全球首套千噸級層狀結構氧化物正極材料濕法合成工藝路線，并設計制造出相應的功能電解液，為鈉離子電池產業生態鏈的建設起到引領作用。
Natrium Energy provides its customers with solutions in three aspects. The cathode materials and electrolytes have been verified by many well-known domestic battery manufacturers, and the batteries reach an energy density of 130-160Wh/kg and a cycle life of over 5000 cycles.
在此基礎上，鈉創團隊在聚陰離子化合物正極材料技術領域取得重要進展。該團隊針對特殊應用場景，發明2D納米結構的碳包覆磷酸釩鈉（Na3V2(PO4)3/C, NVP）納米片及其制備方法（CN201810889365.2）。
Natrium Energy has made some major progresses in polyanion-type cathode materials. The Natrium team has successfully developed a carbon coated Na3V2(PO4)3/C (NVP) with 2D nano-structure (CN201810889365.2) for special applications.
實驗證明，該材料可實現100-300C（12-36秒）的超快速充放電，在200C倍率下經20000次循環，其放電容量保持率為83.3%，為高功率儲能器件設計奠定了良好基礎（Nano Energy, 56(2019)502-511）。
近日，鈉創團隊與上海交通大學和中國石化石油化工研究院緊密合作，開發出易實現工業放大的NVP材料合成新技術，在NVP材料表面均勻包覆3-7nm厚度的導電碳層以增加其導電性。基于所開發的NVP/C材料制成對稱型NVP軟包電池，結果表明，該對稱型NVP軟包電池循環性能優，在1C下循環1000次容量保持率達88%，利用加速量熱（ARC）測量表明，熱失控溫度高達254.4C，其熱穩定性優于NVP/硬碳電池。
Collaborating closely with Shanghai Jiao Tong University and Sinopec Research Institute of Petroleum Processing, Natrium Team has lately developed a new synthetic technique for the NVP materials feasible for industrial scale-up. The NVP nanocrystal is coated by a carbon layer (ca. 3–7 nm) to enhance its electrical conductivity. The soft-packed symmetrical sodium-ion batteries based on the above NVP/C material shows a long cycling stability (88% capacity retention over 1,000 cycles at 1C). It is extremely interesting that the symmetrical battery (thermal runaway temperature is 254.4°C) has shown much higher thermal stability than the hard carbon battery as demonstrated by accelerating rate calorimetry (ARC).
有關機理及安全性研究結果近期發表在《中國化學工程學報》[1]。相關技術已獲中國發明專利（ZL201610241987.5）和美國發明專利（US 2021/0167387 A1）。
Relevant mechanism and safety research results are recently published in Chinese Journal of Chemical Engineering [1]. Related technique has been granted a Chinese patent (ZL201610241987.5) and a US patent (US 2021/0167387 A1) for invention.
在此基礎上，該團隊還以Mn部分取代V改性NVP材料，引入氧化石墨烯（rGO）合成了一種全新的磷酸錳釩鈉（Na4VMn(PO4)3/C-rGO）復合正極材料，以該復合正極制成的鈉離子電池展現出優異的超高倍率性能和長期循環壽命。研究表明，該材料在50 C（1.2分鐘）充放電倍率下的可逆比容量達102 mAh /g，容量保持率達90.6%，經過500次循環容量保持率保持80.4%。還采用原位XRD技術在線測量了復合材料在充放電過程結構相變，為材料實用化奠定了良好的基礎，相關結果發表在國際知名期刊《納米能源》[2] 。
On this basis, Natrium Team further developed a new cathode material (Na4VMn(PO4)3/C-rGO) with V partially replaced by Mn and with rGO as additive. This elaborately designed NVMP/C-rGO composite exhibits an ultrahigh rate capability and long cycle life as cathode in sodium-ion batteries, delivering a reversible capacity of 102 mAh /g at 50 C (1.2 mins) with capacity retention of 90.6% (1 C) and 80.4% (50 C) over 500 cycles. Besides, the in-situ XRD is conducted to analyze the phase transformation of NVMP/C-rGO electrode during the charge and discharge process, laying an excellent foundation for their practical application. Relevant results have been published in the internationally renowned journal Nano Energy [2].
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