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Jiarui He
Jiarui He, Professor at the School of Energy and Environment, Southeast University, and a doctoral supervisor, has been selected for the ‘National High-Level Young Talents’ program. He works on high-safety, high-energy-density, and long-life lithium-ion and metal-sulfur batteries, he has conducted systematic and in-depth research. His achievements in the areas of lithium-sulfur batteries, lithium metal batteries, and electrolytes have been published as the first author/corresponding author in renowned international journals such as Nat. Energy, Nat. Commun., Adv. Mater., Energy Environ. Sci., J. Am. Chem. Soc., Angew. Chem. Int. Ed., and so on. He has authored 55 SCI papers, including 15 ESI Highly Cited Papers and 4 ESI Hot Papers, with over 8,000 total citations. He serves as a reviewer for more than 40 prestigious international journals, including Nature Commun., Adv. Mater., Adv. Energy Mater., Adv. Funct. Mater., ACS Appl. Mater. Interfaces, J. Power Sources. He was awarded the second-class prize in the Sichuan Province Science and Technology Progress Award in 2020 (Natural Sciences category, ranked second).
Presentation title: New strategies to improve performance for sodium metal batteries
Abstract: Sodium–metal batteries (SMBs) are a sustainable, appealing, low–cost alternative to lithium metal batteries due to the high theoretical capacity (1,165 mA h g−1) and abundance of sodium. However, the low compatibility of the electrolyte with the anode and cathode leads to unstable electrode–electrolyte interphases. Here we introduce the concept of using salt as a diluent, which enables the use of a single non–flammable solvent (trimethyl phosphate). By adding sodium nitrate (NaNO3) as a model diluent, we design a 1.1 M NaFSI–NaNO3–trimethyl phosphate (TMP) electrolyte that construct a stable interface with SMBs anode. The carbonate–based electrolyte reacts incessantly with Na(Ni0.3Fe0.4Mn0.3)O2 (NFM) and Na metal due to the existence of free solvent molecules. This leads to severe NFM uncontrollable dendritic sodium development and cracking. This renders them unapplicable for long–stability of SMBs. In the TMP–based localized high–concentration electrolyte (LHCE), like the NaFSI salt, the eutectic NaNO3 diluent molecule strongly interacts with TMP. It subtly substitutions the TMP site in the Na+ primary solvation shell. This solvation structure facilities the formation of a compact SEI on both the cathode and anode derived from the decomposition of electrolyte salts. Such an electrolyte design would therefore enable long–life SMBs. In addition, the use of a single non–flammable solvent such as TMP can improves the safety of the cells. The work demonstrates a promising approach the development of safe, sustainable, high–performance, low–cost SMBs.
Ambient–temperature sodium−sulfur (Na–S) batteries are a sustainable, appealing, and low–cost alternative to lithium–ion batteries due to their high energy of 1274 W h kg−1 and material abundance. However, their practical application is hampered by Na loss due to side reactions with the electrolyte, Na polysulfide (NaPS) shuttling, and dendrite growth. Here, we present effective solutions in terms of both electrolytes and materials. Frist, we demonstrate that a solid–electrolyte interphase rich in inorganic components can be realized at both the sulfur cathode and the Na anode by tweaking the solvation structure of the electrolyte. This transforms the sulfur redox process from conventional dissolution−precipitation chemistry into a quasi–solid–state reaction, which eliminates NaPS shuttling and facilitates dendrite–free Na–metal plating and stripping. Second, we report an intercalation–conversion hybrid positive electrode material by coupling the intercalation–type catalyst, MoTe2, with the conversion–type active material, sulfur. In addition, MoTe2 nanosheets vertically–grown on graphene offer abundant active catalytic sites, further boosting the catalytic activity for sulfur redox.