PDF《SUPPORTING INFORMATION》

1 SUPPORTING INFORMATION Pitaya-Like Microspheres Derived from Prussian Blue Analogues as Ultralong-Life Anodes for Lithium Storage Lianbo Ma,a# Tao Chen,a# Guoyin Zhu,a# Yi Hu,a Hongling Lu,a Renpeng Chen,a Jia Liang,a Zuoxiu Tie,a Zhong Jin,*a and Jie Liu*ab a Key Laboratory of Mesoscopic Chemistry of MOE and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.

b Department of Chemistry, Duke University, Durham, North Carolina, 27708, USA. # These authors contributed equally to this work. *E-mail addresses of corresponding authors: zhongjin@nju.edu.cn (Z. Jin), j.liu@duke.edu (J. Liu)

2 This Supporting Information file includes: S1. The comparison of specific capacities of encapsulated Co3ZnC nanoparticles in pitaya-like microspheres anode and bare Co3ZnC nanoparticle anode. S2. Fig. S1-S21 S1. The comparison of specific capacities of encapsulated Co3ZnC nanoparticles in pitaya-like microspheres anode and bare Co3ZnC nanoparticle anode. The reversible specific capacity of encapsulated Co3ZnC nanoparticles in the pitaya- like microspheres can be calculated as follow: CCo3ZnC・ηCo3ZnC = CTotal C CCarbon・ηCarbon. In this equation, the CTotal is the overall discharge capacity of pitaya-like microsphere anode, CCarbon stands for the discharge capacity of bare carbon frameworks, ηCarbon and ηCo3ZnC present the weight percentage of bare carbon frameworks (31.9%) and bare Co3ZnC nanoparticles (68.1%) determined by the TGA results, respectively. To investigate the discharge capacity of bare carbon frameworks, the Co3ZnC nanoparticles were completely removed by the etching of HF (5 wt.%) and HCl (1.0 M) successively. As shown in Fig. S16, the morphology and structure characterizations confirmed the removal of Co3ZnC nanoparticles. The control sample of bare carbon frameworks shows a discharge capacity of about

436 mAh g-1 after

20 cycles at

100 mA g-1 (Fig. S18a). Therefore, the definite specific capacity of encapsulated Co3ZnC nanoparticles in Co3ZnC/C multicore microspheres can be calculated as follow: CCo3ZnC = (CTotal C CCarbon・ηCarbon)/ηCo3ZnC = (608 C 436*31.9%)/68.1% =

689 mAh g-1. Compared with bare Co3ZnC nanoparticle anode

3 (257 mAh g-1 at 100th cycle), the encapsulated Co3ZnC nanoparticles in pitaya-like microspheres deliver much higher specific capacity. It proves that the electrochemical performance of metal carbides can be greatly enhanced by the special architecture of well-dispersed nanoparticles embedded in 3D conductive carbon frameworks. S2.Fig. S1-S21 Fig. S1. XRD spectrum of Zn3[Co(CN)6]2?nH2O/PVP precursor microspheres.

4 Fig. S2. (a,b) FESEM images of PBA precursor prepared with the halved amount of added PVP in the synthesis procedure.

5 Fig. S3. Morphology characterization of the PBA precursor. (a-d) TEM images of Zn3[Co(CN)6]2?nH2O/PVP precursor microspheres with different magnifications.

6 Fig. S4. EDX spectrum of the pitaya-like microspheres.

7 Fig. S5. Thermogravimetric analysis (TGA) curve of pitaya-like microspheres under air atmosphere with a heating rate of

10 °C/min.

8 Fig. S6. FESEM images of (a) Zn3[Co(CN)6]2?nH2O precursor nanoparticles without PVP and (b) bare Co3ZnC nanoparticles. (c) TEM image of bare Co3ZnC nanoparticles. The morphology characterizations reveal that the bare Co3ZnC nanoparticles are composed of small particles with the size of ~10 nm. (d) EDX and corresponding elemental mapping of (e) raw, (f) C, (g) Co, and (h) Zn elements of