Smart Materials and Design toward Safe and Durable Lithium Ion Batteries

Abstract

Smart electrochemical energy storage devices are devices that can operate autonomously to some extent. Although the conventional electrochemical energy storage devices, e.g., the commonly used lithium‐ion batteries (LIBs), may be externally monitored in terms of their voltage and current output to reflect the state of health for the devices, it is extremely important to exploit materials and devices that are intrinsically smart enough to be capable of rapidly self‐detecting and responding to faults, such as interior short circuits, overheating, abnormal capacity drop, and other types of mechanical/chemical damage. These “smart” features could significantly enhance the safety characteristics and durability of LIBs, which is essential for future usage. Therefore, recent achievements toward smart materials and design strategies for safer and more durable LIBs are summarized. The main categories are as follows: 1) New materials: This category mainly includes smart electrode materials with thermal/electrical/mechanical self‐response functions, and self‐response separators to suppress thermal runaway/lithium dendrite growth; 2) New chemistries: This category mainly includes electrolytes with reversible self‐protecting functions; and 3) New architectures with novel functions, such as shape‐recovery, self‐heating, and self‐monitoring. Besides the working mechanisms, the challenges that must be overcome for smart LIBs to be adopted in practical applications are also discussed.

Mitigating Thermal Runaway of Lithium-Ion Batteries

“…''Smart Batteries'' with Smart Materials and Design Smart batteries contain components that can operate autonomously under specific cases. 66 Smart materials for battery safety design rely on mechanisms that can release negative response toward faults. As TR is accompanied by temperature rise, thermal-responsive materials are favored as smart materials for increasing the electric resistance, 67 blocking the ionic transport, 21 and releasing a poisoning reagent that can suppress TR 29 at specific temperatures.…”

“…The suppression of Li plating is accomplished by self-healing separators. 66 Silica nanoparticles embedded in separators can react with the penetrating lithium dendrites, thereby retarding the growth of the lithium dendrite. 70 A sandwich structure is also beneficial for the early detection of an internal short circuit that is induced by dendrite growth.…”

Direct Nano‐Synthesis Methods Notably Benefit Mg‐Battery Cathode Performance

“…[ 1–3 ] Rechargeable batteries offer viable approaches to achieve these goals, but improvements are needed to progress beyond current state of the art lithium ion batteries (LIBs) which are limited by economic factors and safety concerns. [ 4–6 ] As an earth‐abundant metal and divalent cation, magnesium‐based battery technology provides large theoretical volumetric energy densities at a fraction of the cost of LIBs. [ 7,8 ] Furthermore, rechargeable magnesium (Mg) batteries are promising candidates for electrochemical energy storage due to limited dendritic growth and good safety of the Mg metal anode.…”

Advances in Prevention of Thermal Runaway in Lithium‐Ion Batteries

“…Apart from conductive additives, the polymer binders inside the cell can also be designed as temperature sensitive, ideally beginning at temperatures below 100 C. For example, LiCoO 2 sandwiched with poly(methyl methacrylate) mixed with Super P carbon black was found to have PTC properties, increasing resistance at 80-120 C such that the cell capacity of 140 mAh.g À1 decreases to 8.4 mAh g À1 at 110 C, blocking transfer of most of the current through the cell. [115] Carbon/polyethylene compostites are another PTC material; [116] the challenge is to improve the contact between the conductive particles embedded in the polymer matrix.…”