Recently, Assistant Professor Lei Tian, Professor Caizhen Zhu and Professor Jian Xu’s team from the College of Chemistry and Environmental Engineering at Shenzhen University published the latest research progresses about high-performance solid-state lithium metal batteries on journal《Advanced Materials》.

Solid polymer electrolyte (SPE) has become an important development direction and theoretical research hotspot of solid-state battery industrialization due to its excellent machining performance and interface compatibility. However, there are still many defects that seriously hinder its further practical application, such as low ionic conductivity at room temperature (about 10^-7 S cm^-1), poor interface contact with electrode material (interface impedance increases), poor stability (thermal stability and interface stability), low mechanical strength (difficulty in inhibiting lithium dendrites and short circuits), etc. In view of the above problems that limit the large-scale application of solid polymer electrolyte, the preparation strategy of “in-situ solidification” for solid-state battery emerged. In other words, the liquid precursor is in-situ cured inside the cell under thermal, optical or electrical conditions, achieving hyper-conformal interface compatibility and greatly solving the solid/solid interface contact problem.

Many research work has been carried out around liquid-solid transition methods, including thermal-initiated free radical polymerization, ring ether ring-opening polymerization and in-situ gelation. Organic/inorganic hybrid cross-linked PDOL constructed with molecular design, combining the advantages of good processability, interface contact and electrode compatibility of polymer materials with the advantages of excellent ionic transport, thermal stability, flame retardant of inorganic materials, can effectively solve the above problems.

This work propose a strategy of organic/inorganic hybrid crosslinked polymer electrolyte (HCPE) via in-situ polymerization of DOL and glycidyl ether oxypropyl cage polyhedral silsesquioxane (PS) as a cross-linking agent and hybrid center inside a battery cell. The formed hybrid crosslinked network facilitates the electrochemical stability and Li+ transport kinetics, so that the prepared PDOL-5%PS HCPE exhibits a superior ionic conductivity of 2.22 × 10^-3 S cm⁻¹ at 30°C, a ultrahigh Li+ transference number (t_Li+) of 0.88, and a wide electrochemical stability window of 5.2 V. These results allow highly stable lithium stripping/plating cycling for over 1000 h at 1 mA cm^-2. Moreover, the assembled LFP|PDOL-5%PS|Li battery exhibits a high reversible discharge specifific capacity of 123.3 mAh g-1 at 2 C and a superior capacity retention of 92.1% after 600 cycles. This work proposes that HCPE overcomes the challenges of easy degradation and poor safety of polyether electrolytes, enabling “in-situ solidification” to move further towards practical applications.

The research article "Hybrid Crosslinked Solid Polymer Electrolyte via In-Situ Solidification Enables High-Performance solid-state Lithium Metal Batteries" is published in 《Advanced Materials》 (Impact factor 29.4, JCR Region 1, Top Journal)，authored by Master's student Kexin Mu is the first author of this paper. Assistant Professor Lei Tian and Professor Caizhen Zhu are the corresponding authors of this paper. The corresponding unit is the School of Chemical and Environmental Engineering, Shenzhen University.

The authors are grateful for the support from the National Natural Science Foundation of China (Nos. 22001175, 51973118, 22175121, and 52003160), Key-Area Research and Development Program of Guangdong Province(2019B010929002 and, 2019B010941001), the Natural Science Foundation of Guangdong Province(2020A1515010644), the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2019ZT08C642), Guangdong Basic and Applied Basic Research Foundation (2023A1515010045), and Shenzhen Science and Technology Program (JCYJ20210324095412035, 20220808121346001), and sponsored by CNPC Innovation Fund (2022DQ02-0401).

Article details:

Kexin Mu, Dai Wang, Weiliang Dong, Qiang Liu, Zhennuo Song, Weijian Xu, Pingping Yao, Yin’an Chen, Bo Yang, Cuihua Li, Lei Tian,* Caizhen Zhu,* Jian Xu, Hybrid Crosslinked Solid Polymer Electrolyte via In-Situ Solidification Enables High-Performance Solid-State Lithium Metal Batteries Adv. Mater. 2023, 202304686.

See full text link: https://doi.org/10.1002/adma.202304686