Superior high rate capability of size-controlled LiMnPO₄/C nanosheets with preferential orientation

Abstract

Rectangular-shaped LiMnPO4/C nanosheets prepared via a solvothermal process exhibited high discharge capacities near the theoretical value and stable cycling retentions.

Deep Eutectic Solvent Synthesis of LiMnPO4/C Nanorods as a Cathode Material for Lithium Ion Batteries

“…Figure 8 compares the cycling performance of the LiMnPO 4 /C prepared in ethylene glycol/choline chloride and ethylene glycol solvent, respectively. As shown in Figure 8 , the LiMnPO 4 /C prepared in ethylene glycol solvent gave a specific discharge capacity of 117 mAh·g −1 with a capacity retention ratio of 88% after 50 cycles at 1 C, which is close to that of LiMnPO 4 /C prepared in the ethylene glycol solvent [ 18 , 30 , 33 ], while the LiMnPO 4 /C prepared in ethylene glycol/choline chloride delivered 128 mAh·g −1 with a capacity retention ratio of 95% after 50 cycles at 1 C. The performance of LiMnPO 4 /C prepared in ethylene glycol/choline chloride was much better than that in ethylene glycol, indicating that choline chloride plays a more important role during the synthesis of LiMnPO 4 in the DES. However, the interaction of choline chloride and ethylene glycol in the DES is under further investigation.…”

“…However, LiMnPO 4 suffers from slow lithium ion diffusion (10 −15 cm·s −1 ) and poor electronic conductivity (10 −10 cm·s −1 ), due to the heavy polarized holes localized on the Mn 3+ sites and the interfacial strain that exists between the LiMnPO 4 and MnPO 4 phases during charge/discharge processes [13,14,15]. In order to overcome these drawbacks, three approaches have been adopted: (1) reducing the particle size and controlling the morphology [16,17,18]; (2) coating a conductive layer on the surface of LiMnPO 4 [19,20,21,22]; and (3) doping with cations [23,24,25,26]. …”

“…In these adopted approaches, hydrothermal/solvothermal methods have attracted particular attention owing to the controllable synthesis of LiMnPO 4 /C with a special morphology [ 2 , 20 , 21 , 33 , 34 , 35 ]. Therefore, various special morphologies such as nanoplates [ 16 , 21 , 36 ]; nanorods [ 10 , 33 , 35 ]; nanosheets [ 18 , 37 ]; flower-like nanostructures [ 34 , 38 ]; hemoglobin [ 39 ]; and wedges [ 40 ] were prepared using the hydrothermal/solvothermal method to enhance the electrochemical performance of LiMnPO 4 . LiMnPO 4 nanoplates were synthesized using an ethylene glycol (EG)-assisted solvothermal approach and delivered a discharge capacity of 92 mAh·g −1 at 0.5 C [ 32 ].…”