Chen Shimou

Chen Shimou is a professor and doctoral supervisor at the School of Materials Science and Engineering, Beijing University of Chemical Technology. Mainly engaged in research on key materials, energy storage devices, and industrial applications of lithium-ion batteries, solid-state batteries, and zinc ion batteries. In J Am. Chem SOC; Angelw Chem Int. Ed; Adv. Material; Energy Environment Sci; ACS Nano; Adv. Function More than 160 SCI papers have been published in journals such as Mater, and 46 national invention patents and 28 authorizations have been applied for. Undertake more than 10 national key research and development projects, including the National Natural Science Foundation of China's Excellent Youth, General, and Major Research Program Cultivation, the Chinese Academy of Sciences Nano Leading Special Project, the Beijing Municipal Science and Technology Commission Major Project, and the Zhengzhou Municipal Major Special Project. I graduated with a doctoral degree from the Shanghai Institute of Applied Physics, Chinese Academy of Sciences in 2007. In 2008, I received a postdoctoral degree from the JSPS program at Nagoya University. In 2011, I became a MANA researcher at the National Institute of Materials and Materials in Japan. In 2012, I became a member of the Hundred Talents Program, Research Fellow, and Doctoral Supervisor at the Institute of Process Engineering, Chinese Academy of Sciences. In 2020, I became a professor at Beijing University of Chemical Technology. Has won the Youth Innovation Award for Ionic Liquids and Green Processes in 2014, and excelled in the final assessment of the Hundred Talents Program of the Chinese Academy of Sciences in 2017; Selected as a talent for entrepreneurship and innovation in Jiangsu Province in 2017; In 2018, he was selected as a national leading talent in Zhihui Zhengzhou. In 2019, he received funding from the National Natural Science Foundation of China's Excellent Youth Program. In 2020, he was selected as a Outstanding Youth of the Hebei Provincial Natural Science Foundation of China. In 2023, he was selected as a Fellow of the Royal Society of Chemistry in the United Kingdom.

Ø  High safety and high energy density lithium-ion batteries

1. Motivation

With the rapid development of portable electronic devices, new energy vehicles, large-scale energy storage, aerospace, etc, the performance of lithium ion batteries (LIBs) has put forward higher requirements. Improving energy density and safety is the focus and difficulty of LIBs research and development. The development of high-performance LIBs has become an important challenge facing the current academic and industrial industry. With the successful development of a series of high-voltage cathode and high-capacity anode materials, the breakthrough of electrolyte technology has become the bottleneck for further improving the performance of LIBs, and the core problem is how to improve the stability of the electrolyte at high voltage and its adaptation to positive and negative electrode materials.

2. Strategies and novelties

(1)      New concepts and mechanisms such as orientation arrangement and polymerization of ionic liquid on electrode surface have established, which can solve the problems of poor stability of the electrode-electrolyte interfacial film in commercial liquid electrolyte system. The uniform and continuous ionic liquid-inorganic composite interface protection layer is constructed, which effectively inhibits the side reaction between the electrolyte and the electrode material, and greatly improves the performance of the lithium ion batteries.

(2)      DOE design and high throughput experiment were adopted to optimize the solvent, lithium salt and additives of the electrolyte. The molecular reaction mechanism and regulation mechanism of solid electrolyte interface (SEI) formed by a series of functional additives and the liquid electrolyte on the surface of the anode and cathode were studied by photoelectron spectroscopy, synchrotron radiation XAFS, and other method.

3. Achievements

(1)      Hundreds of electrolytes using ionic liquids as additives or co-solvents have been designed and prepared, and some of the electrolytes have electrochemical windows up to 5.0V.

(2)      A new high-energy density LIBs system based on high-voltage electrolytes was developed. The charging cut-off voltage of lithium-manganese-rich layered oxides was effectively increased by using the ionic liquid high-voltage electrolyte, and the energy density of the new system reached more than 400 Wh/kg.

(3)      Regarding this topic, 18 SCI-indexed papers were published and 8 patents were authorized.

Ø  Ionic liquid based high-performance solid-state batteries

1. Motivation

The poor compatibility of the electrodes-electrolyte interfaces of rechargeable lithium metal batteries with solid-state electrolytes limit their wide applications, to accelerate the commercialization of the solid state batteries, we have to overcome the following challenges:   (1) Developing high-efficiency strategies to solve the incompatibility for the practical implementation of high-voltage and high-energy solid-state lithium metal batteries simultaneously. (2) Developing solid-state electrolytes with good compatibility for high-voltage cathodes and reliable operation of batteries over a wide-temperature-range. (3) Developingultralong lifetime with high ionic conductivity, interfacial stability of lithium metal in high-performance solid-state lithium metal batteries.

2. Strategies and novelties

(1)     Through surface in situ polymerization of polymerizable ether-based electrolytes to create durable and adjustable solid polymeric electrolytes at the cathode side, which simultaneously integrates the as-formed polyether/LiTFSI SPE with Ni-rich NCM cathodes, Al current collectors, and metal anodes for their long-term cycling stability, durable high-voltage tolerance and Li-dendrite inhibition.

(2)     Designing a high polymerization degree and a soothing curing time nano-hierarchical quasi solid-state poly-ether electrolyte, initiated by designed hybrid initiator system, as an interface encapsulation on the surface of the cathode to mitigate interfacial instability in thermodynamic and electrochemical aspects.

(3)     Designing a novel polycarbonate-polyethylene oxide based solid polymer electrolyte with a double layered structure via drop casting and UV photocuring, the balances of coupling/decoupling in Li⁺…TFSI^– and Li⁺…PAN/PVEC facilitate a fast Li⁺transport, and possess oxidative stabilitywith high-voltage cathode and good reductive stability with Li metalanode.

(4)     Designing the free amide molecules of deep eutectic solvents nanoconfined by UiO-66-NH₂ in the polyethylene oxide matrix solid electrolyte, which contributes to uniform lithium deposition on the lithium metal anode.

(5)     Proposing a mechanism of regulating the cathode/anode interfaces by azo compounds with different electron groups in-situ constructing, the free radicals formed by electron-withdrawing/electron donating group can be grafted onto different electrodes on demand, thereby forming stable interfaces at both cathode and anode sides.

3. Achievements

(1)     The integrated interfacial engineering fabricates a homogeneous solid electrolyte with optimized interfacial interactions, the in-situ polymerization enables a uniform adjustment of solid electrolyte composition by dissolving additives such as Na⁺ and K⁺ salts, which presents prominent cyclability in symmetric Li cells (>300 cycles at 5 mA cm⁻²). The assembled LiNi_0.8Co_0.1Mn_0.1O₂ (4.3 V)||Li batteries show excellent cycle life with high Coulombic efficiencies (>99%).

(2)     The nano-hierarchical quasi solid-state poly-ether electrolyte presents highly compatible electrolyte/electrode interfaces in thermodynamic and electrochemical aspects, showing a promising wide application in Li, Na, K, and Zn metal batteries. The SPEE enables outstanding cycle-stability for wide-temperature operation (15-100 °C) and 4 V-above batteries (Li||LiCoO₂ and Li||LiNi_0.8Co_0.1Mn_0.1O₂).

(3)     The obtained double-layered polymer electrolyte exhibits high Li⁺transference number (0.602) and high ionic conductivity (1.56 × 10^–4 S cm^–1, 20 °C), and delivers high safety and high stable performances under various extreme conditions in LiFePO₄ and LiNi_0.8Co_0.1Mn_0.1O₂ battery.

(4)     The deep eutectic solvents cell not only exhibits an excellent symmetrical electrochemical cycling performance more than 3600 h is achieved, extended by ~10 times comparing to the reference.

(5)     Regarding this topic, 20 SCI-indexed papers were published and 8 patents were authorized.

Ø  High performance electrode materials for sodium ion batteries

1. Motivations

As an energy storage system that can replace lithium-ion batteries, sodium ion batteries have the advantage of analogous properties of Li, low cost, high safety and have attracted increasing attentions. However, the sluggish kinetics of sodiation/desodiation process caused by the large Na⁺ radius (1.02 Å) results in the unavailable of conventional electrode materials of LIBs and undesirable electrochemical performance. We have designed and synthesized transition metal sulfide based negative electrode materials for sodium ion batteries with different microstructures. We have carefully studied the structure-activity relationship between structure, composition, and electrochemical performance, proposed corresponding laws, and elucidated the growth mechanism of the synthesized composite structure, providing theoretical guidance for the design and development of efficient sodium ion battery electrode materials.

2. Strategies and novelties

(1)  Heterostructures strategy: Se vacancies and heterostructure engineering are utilized to improve the Na⁺-storage performance of transition metal selenides anode. The experimental results coupled with theoretical calculations reveal that the successful construction of the Se vacancies and heterostructure interfaces can effectively lower the Na⁺ diffusion barrier, accelerate the charge transfer efficiency, improve Na⁺ adsorption ability, and provide an abundance of active sites. This strategy facilitates an in-depth understanding of the synergistic effect of vacancies and heterojunctions in improving the Na⁺ reaction kinetics, providing an effective strategy to the rational design of key materials for high efficiency rechargeable batteries.

(2) Bond engineering strategy: By heterointerface with bond engineering strategy to realize outstanding Na⁺-storage performance. Theoretical calculations on the stress deformation confirm the construction enables excellent resistance-to-deformation ability but also exhibits strong mechanically stable against sodiation-desodiation, result in an impressive cycling stability and superb rate performance for Na⁺-storage. The proposed engineering strategy and results provide new insight to design carbon-free advanced electrodes for future practical applications.

(3) Strain-modulating strategy: Carbon-free anodes play a vital role in developing rechargeable batteries with high volumetric capacities, however, the huge volume expansion effect brought by the large Na⁺ leads to low reversibility. Through strain-modulating, the anode materials can alleviate the stress during cycling processes and subsequently improves the stability of the assembled batteries. Additionally, the well-formed structure by the strategy also contributes to the rapid Na⁺ diffusion kinetic, increased charge transfer, and good reversibility of the transformation reactions, endowing the appealing rate capability of electrode. The proposed design strategy provides new insight and inspiration to aid in the ongoing quest for advanced electrode materials with high tap densities and excellent stability.

3. Achievements

(1)    We have successfully synthesized various electrode materials through the above strategies and applied for sodium ion batteries, improving their electrochemical performance, including increased capacity, enhanced cycling stability, and accelerated ion diffusion kinetics, which provides new research insight and inspiration for the exploration of electrode materials in sodium ion batteries.

(2)    Regarding this topic, 6 SCI-indexed papers were published and 8 patents were publicized.

Ø  New materials and new systems of high-performance zinc-ion batteries

1. Motivations

Zinc ion batteries (ZIBs) reached the top priority due to the merits of outstanding theoretical capacity (820 mAh g⁻¹), low redox potential (-0.76 V vs standard hydrogen electrode), and an abundance of Zn metal. However, in the aqueous electrolyte, the Zn anode is prone to the side reactions of dendrite growth, metal corrosion and HER, while cathode also suffers from ion dissolution and structural collapse, which seriously affects the cycle stability of ZIBS. In addition, the presence of H₂O results in narrow electrochemical window and working temperature range of electrolytes, thereby curbing the further development and application of ZIBs. So, we propose some strategies to address the aforementioned issues.

2. Strategies and novelties

(1)  The semi-immobilized interface layer was prepared to improve electrochemical performance of zinc anode at wide temperatures by grafting ionic liquid onto the surface of nano-silica and mixing it with polyacrylonitrile. The study shows that the free phase of the interface layer can weaken the interactions among the components of the electrolytes, promote the desolvation behavior and transport kinetics of Zn²⁺, and suppress the side reactions at the interface; while the immobilized phase of the interface layer can reduce the contents and activity of H₂O molecules, and guarantee uniform Zn²⁺ nucleation and planer deposition along (002) plane.

(2)  The self-separating interface layer was constructed on Zn anode surface to optimize electrodes and electrolytes stability by coupling sodium tricyanomethane and polyacrylonitrile, realizing the excellent performance of AZIBs at a wide temperature range. The interface layer can regulate the migration pathway and nucleation-growth-deposition behavior of Zn²⁺ and inhibit metal corrosion and dendrite growth, improving the stability of the Zn anode; at the same time, the separating phase of interface layer can diffuse into the electrolyte, regulate the solvation behavior of Zn²⁺, and form a stable interface layer on the cathode surface, leading to excellent structural stability of the cathode.

(3)  A new strategy to dynamically regulate the electrode/electrolyte interface was proposed to improve the electrochemical performance of zinc-iodine batteries by using tris(2-cyanoethyl) borate as an additive. The additive can regulate the hydrogen bond network of H₂O molecules and the solvation structure of Zn²⁺, improving the kinetics of Zn²⁺ ion transport; The additive also can evolve into a dense, stable gradient solid electrolyte interface layer, enhancing the cycle stability and reversibility of the zinc anode; in addition, the additive can be adsorbed on the surface of the cathode surface to inhibit the dissolution of the iodine positive electrode, accelerate the conversion of polyiodides, and improve the ion diffusion-conversion kinetics on cathode side.

(4)  We construct a self-adaptive electric double layer (EDL) on the interfaces of the anode and cathode of zinc metal batteries. It is enabled by adding zwitterionic ionic liquids (ZIL) additives in the electrolyte, which can selectively gather on the electrode surface by the cationic and anionic moieties under the electric field, forming a dynamic electrostatic shielding layer on the Zn anode and a unique water-poor interface on the cathode. This special self-adaptive EDL driven by the electric field can facilitate homogeneous Zn²⁺ deposition and circumvents the dissolution of the cathode material.

3. Achievements

(1)      The semi-immobilized interface layer strategy significantly improves the thermodynamic stability and ion transport kinetics at the zinc anode/electrolyte interface, and the various full batteries of Zn//MnO₂, Zn//MgV₂O₅ and Zn//Mg-V₂O₅ exhibit excellent rate performance of 20 A g^-1 and ultralong life of 80000 cycles in extreme conditions.

(2)   Dynamic modulation of electrode/electrolyte interface strategy ensures that Zn anode shows excellent cycle stability of more than 1500 hours and large rate performance of 20 mA cm^-2, and the Zn//I₂ full battery still exhibits an ultra-long lifespan of more than 7000 cycles and good energy density at 100 % zinc usage rate.

(3)  Regarding this topic, 15 SCI-indexed papers were published.

1. New Energy Materials and Devices

2. Electrochemical Principles and Measurement Methods