Engineering 3D bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite for lithium storage with high rate capability and long cycle stability

Abstract

A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li+ diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe3+ to Fe2+ and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li+ intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method.

Preparation of LiFePO4/C Cathode Materials via a Green Synthesis Route for Lithium-Ion Battery Applications

“…N peak appears at 2.63 V (characteristic of Fe 3+ in Fe 2 O 3 ), indicating that all the iron atoms in the LiFePO 4 /C composite are Fe 2+ [40]. The two peaks around at 3.34 and 3.53 V (vs. Li + /Li) are attributed to the Fe 2+ /Fe 3+ redox reaction, which corresponds to lithium extraction and insertion in LiFePO 4 crystal structure [41]. Furthermore, the two peaks show a narrow potential separation of 0.19 V and exhibit good symmetric and poignant shape, which imply a good electrochemical performance for lithium ion batteries.…”

“…The peak position shifts and the potential separation between two peaks broadens gradually as the scan rate increases. Previous literature has reported that the diffusion coefficient of lithium ions (D Li ) can be determined from a linear relationship between peak currents (i p ) and the square root of the scan rate (v 1/2 ) based on the Randles–Sevcik equation [41,42,43]: Ip=2.69×105n3/2ACD1/2v1/2 where I p (A) is the current maximum, n is the number of electrons transfer per mole (n = 1), F (C/mol) is the Faraday constant, A (cm 2 ) is the electrode area (1.77 cm 2 ), C (mol/cm 3 ) is the lithium concentration in the LiFePO 4 /C composite, v (V/s) is the scanning rate, D Li (cm 2 /s) is the lithium diffusion coefficient, R (J/K·mol) is the gas constant, and T (K) is the temperature. Figure 4c shows the linear relationship between peak currents (I p ) and the square root of the scan rate (v 1/2 ).…”

Kajian Aplikasi Bahan Dengan Konduktivitas Listrik Tinggi Untuk Meningkatkan Unjuk Kerja Baterai Ion Litium

“…Perkembangan terbaru menunjukkan bahwa untuk meningkatkan unjuk kerja baterai ion litium terutama konduktivitas listrik, tidak hanya mencampurkan bahan berkonduktivitas tinggi saja, namun juga ditentukan oleh cara, konstruksi dan arsitektur yang dibangun oleh berbagai bahan secara kompleks, bahkan sampai pada skala nanometer [32][33][34][35][36][37][38][39][40][41][42][43][44].…”

“…Bahan aktif lain untuk anoda seperti kobalkobal oksida, nikel oksida dan tembaga oksida juga memberikan hasil yang selaras [10,39,53]. Untuk bahan silikon, percobaan Sternad dkk membuktikan bahwa struktur yang terorientasi memberikan unjuk kerja yang lebih baik [12].…”

The Surface Coating of Commercial LiFePO4 by Utilizing ZIF-8 for High Electrochemical Performance Lithium Ion Battery

“…The high cycle stability mainly depends on the structural stability of the electrode material at different charge and discharge current rates [ 19 , 20 ]. For LFP cathode material, both volume shrinkage (charge/lithium ion deintercalation) and expansion (discharge/lithium ion intercalation) will lead to structural damage and thus cause capacity decline [ 21 ]. It is demonstrated that the suitable coating layer with porous structure can effectively improve the structural stability of the active material by buffering volume change [ 22 , 23 ].…”