Selenium infiltrated hierarchical hollow carbon spheres display rapid kinetics and extended cycling as lithium metal battery (LMB) cathodes

Document Type

Article

Publication Date

9-14-2021

Abstract

Lithium metal-selenium (Li-Se) batteries offer high volumetric energy but are limited in their cycling life and fast charge characteristics. Here a facile approach is demonstrated to synthesize hierarchically porous hollow carbon spheres that host Se (Se@HHCS) and allow for state-of-the-art electrochemical performance in a standard carbonate electrolyte (1 M LiPF6in 1 : 1 EC : DEC). The Se@HHCS electrodes display among the most favorable fast charge and cycling behavior reported. For example, they deliver specific capacities of 442 and 357 mA h g−1after 1500 and 2000 cycles at 5C and 10C, respectively. At 2C, Se@HHCS delivers 558 mA h g−1after 500 cycles, with cycling coulombic efficiency of 99.9%. Post-mortem microstructural analysis indicates that the structures remain intact during extended cycling. Per GITT analysis, Se@HHCS possesses significantly higher diffusion coefficients in both lithiation and delithiation processes as compared to the baseline. The superior performance of Se@HHCS is directly linked to its macroscopic and nanoscale pore structure: the hollow carbon sphere morphology as well as the remnant open nanoporosity accommodates the 69% volume expansion of the Li to Li2Se transformation, with the nanopores also providing a complementary fast ion diffusion path.

Identifier

85114131381 (Scopus)

Publication Title

Journal of Materials Chemistry A

External Full Text Location

https://doi.org/10.1039/d1ta04705a

e-ISSN

20507496

ISSN

20507488

First Page

18582

Last Page

18593

Issue

34

Volume

9

Grant

1911905

Fund Ref

U.S. Department of Energy

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