In:
Advanced Engineering Materials, Wiley, Vol. 22, No. 12 ( 2020-12)
Abstract:
Nanocrystallization can shorten the Li + transport distance, resulting in the enhancement of electrochemical activity for cathode materials. However, nanocathode materials tend to be thermally unstable, further leading to poor electrochemical performance of a battery system. This disadvantage can be especially detrimental for thermal batteries because they are often operated at high temperatures (≥450 °C). Herein, the decomposition character of NiS 2 at 500 °C is investigated. The decomposition temperatures of NiS 2 are found to decrease from 510 to 350 °C with the grain size decreasing to 39 nm, due to the dramatically increased surface energy. The decomposition product is confirmed to be NiS, evidenced by a high‐temperature X‐ray diffractometer. The useful mass of the cathode will reduce once the discharging temperature is higher than 500 °C. Namely, although the small grain size shorthens the Li + transport distance, the discharge performance of the NiS 2 cathode may also decrease due to its inferior thermal stability. For the Li‐B/LiF–LiCl–LiBr/NiS 2 system, the NiS 2 with the grain size of 70 nm shows the highest specific capacity of 831 mAh g −1 under the discharging temperature of 500 °C, with the cut‐off voltage of 0.5 V, compared with other grain sizes from 39 to 112 nm.
Type of Medium:
Online Resource
ISSN:
1438-1656
,
1527-2648
DOI:
10.1002/adem.202000299
Language:
English
Publisher:
Wiley
Publication Date:
2020
detail.hit.zdb_id:
2016980-2
detail.hit.zdb_id:
1496512-4
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