The continuous energy density increase of lithium ion batteries (LIBs) inevitably accompanies with the rising of safety concerns. Here, the thermal characteristics of a high-energy 5 Ah LiNi0.5Co0.2Mn0.3O2/graphite pouch cell using a thermally stable dual-salt electrolyte were analyzed. Heat determination during cycling at two boundary scenarios of adiabatic and isothermal environment clearly states the necessity of designing an efficient and smart battery thermal management system. More importantly, it is innovatively proposed that the hydrogen anion (H−) induced H2 releasing at anode side and H2 migration to cathode side is the rooted thermal runaway trigger of the pouch cell, while the phase transformation of lithiated graphite anode and the O2-releasing by delithiated cathode are just accelerating factors for thermal runaway. These findings will shed promising lights on thermal runaway route map depiction and thermal runaway prevention, as well as formulation of electrolyte for high energy safer LIBs.

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There is NO Competing Interest.
This is a list of supplementary files associated with this preprint. Click to download.
Dataset 1
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Posted 08 Jan, 2021
Posted 08 Jan, 2021
The continuous energy density increase of lithium ion batteries (LIBs) inevitably accompanies with the rising of safety concerns. Here, the thermal characteristics of a high-energy 5 Ah LiNi0.5Co0.2Mn0.3O2/graphite pouch cell using a thermally stable dual-salt electrolyte were analyzed. Heat determination during cycling at two boundary scenarios of adiabatic and isothermal environment clearly states the necessity of designing an efficient and smart battery thermal management system. More importantly, it is innovatively proposed that the hydrogen anion (H−) induced H2 releasing at anode side and H2 migration to cathode side is the rooted thermal runaway trigger of the pouch cell, while the phase transformation of lithiated graphite anode and the O2-releasing by delithiated cathode are just accelerating factors for thermal runaway. These findings will shed promising lights on thermal runaway route map depiction and thermal runaway prevention, as well as formulation of electrolyte for high energy safer LIBs.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6
There is NO Competing Interest.
This is a list of supplementary files associated with this preprint. Click to download.
Dataset 1
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