Energy storage is a key supporting technology for the energy revolution. The development of energy storage is an important means to promote the integration and consumption of high proportions of renewable energy such as wind and solar energy. It is important to improve the independent controllability of key equipment and systems, and realize the transformation of my country’s energy structure and energy. The key to supply security is also an urgent need for key common supporting technologies to achieve carbon peak and carbon neutrality.
With the goal of sustainable development, our research group is engaged in innovative research in the fields of energy materials and energy chemistry, especially lithium metal, lithium-sulfur batteries, and energy electrocatalysis. The specific research work includes:
(1) Lithium metal batteries and enery chemistry: Lithium bond chemistry, ion–solvent complex, and chemsitry about lithium metal and electrolytes
The energy chemistry of lithium is the core foundation of the energy conversion and storage process of lithium batteries. We seek to understand and explore the energy chemistry of lithium at electronic, atomic, molecular and material scale, including the existence state, the interactions with other atoms and molecules, transport mechanism, thermodynamic and kinetic features of (electro-) chemical reactions, and temporal and spatial behavior of lithium atom or ion in lithium batteries by developing theoretical simulation and experimental tools. We focus on the theory of lithium bond, solvation chemistry in electrolyte, the formation process of electrode/electrolyte interphase, and the charge transfer mechanism, aiming to provide guidance for the design of electrode, electrode, and interphase.
(2) Lithium metal anodes: Highly safe, high-energy density, and long-cycling composite lithium metal anodes and solid-state batteries
Lithium metal anode is the basis material of high-energy-density rechargeable batteries. Stable lithium metal anode is the key to promote the practical applications of high-safety and high-energy-density batteries. We seek to disclose the key issues hindering the stability of lithium metal anode under practical conditions. We develop the structure design of three-dimensional hosts, lithiophilic materials, emerging liquid electrolytes, new organic-inorganic composite solid electrolytes, artificial interfaces to construct long-cycling and high-specific-capacity composite lithium anodes. We explore the strategies to achieve high-energy-density lithium pouch cells based on liquid, solid-state, and all-solid-state electrolytes to promote the use of lithium metal batteries.
(3) Lithum–sulfur batteries: Long-cycling, low-expense, and high-energy-density lithium–sulfur batteries
Lithium–sulfur batteries are highly considered as promising next-generation energy storage technology due to the ultrahigh theoretical energy density of 2600 Wh kg−1. Focusing on the key electrochemical process, Prof. Zhang’s research group performed a series of researches on reaction mechanism and regulation strategies regarding constructing cathode skeleton to promote electron/ion conductivity, designing homogeneous/heterogeneous kinetic promoters to boost the sulfur redox kinetics, regulating the solvation structure of polysulfides to improve reaction reversibility, and protecting lithium metal anode by inhibiting side reactions to realize practical lithium–sulfur pouch cells with high energy density and long cycling lifespan and provide new understanding on reaction mechanism, regulation strategy, and application.
(4) Energy and electrocatalysis: Zinc–air batteries, oxygen reduction and oxidation catalyst, three-phase electrocatalysis
Rechargeable zinc–air batteries have attracted intensive attentions because of their high energy density, low cost, environmental friendliness, and safety, whose actual performances are severely limited by the sluggish kinetics of the cathodic oxygen reduction and evolution reactions at the three-phase boundaries. To address the above issue, Prof. Zhang’s group proposed the anionic regulation strategy and developed a series of presice synthesis methods to promote the intrinsic activity of noble-metal-free electrocatalysts, designed strongly coupled interfaces to promote interfacial electron transfer, and desinged hierarchical air cathode structures to realize high-performance noble-metal-free bifunctional oxygen electrocatalysts and corresponding zinc–air batteries capable to cycle stably at high rate and high capacity.
(5) Machine-learning assisted functional material design
The rapid development of computer technology has greatly promoted the new paradigm of energy material design based on big data, which is expected to greatly reduce the time and expense of material design. On the one hand, build a multi-scale simulation method based on density functional theory, molecular dynamics simulation and phase field theory, establish a large database of energy material systems at the molecular level, and quantitatively understand the structure-activity relationship of functional materials, so as to realize the rational design and high-throughput screening of energy materials. On the other hand, based on the understanding of the micro-mechanism of the energy system related to lithium batteries, the combination of theory and experiments should be combined to accurately predict battery cycle life and high and low temperature performance.