Lithium-ion batteries break energy density record
Researchers have succeeded in making rechargeable pouch-type lithium batteries with a record-breaking energy density of over 700 Wh/kg. The new design comprises a high-capacity lithium-rich manganese-based cathode and a thin lithium metal anode with high specific energy. If developed further, the device could find use in applications such as electric aviation, which requires much higher energy density batteries than those available today.
Achieving a truly carbon-free economy, however, will require better-performing batteries than current lithium-ion technology can deliver. In electric vehicles, for example, a key consideration is for batteries to be as small and lightweight as possible. Achieving that goal calls for energy densities that are higher than 400 Wh/kg. The problem is that today’s lithium-ion batteries mainly contain intercalation-type cathodes (for example, LiFePO4, LiCoO2 or LiNixMnyCozO2, x+y+z=1) and graphite-based anodes, and the energy density of these electrodes is approaching its upper limit.
High charge-discharge voltage
In the new work, the researchers led by Xiqian Yu and Hong Li of the Institute of Physics, Chinese Academy of Sciences in Beijing, have manufactured practical pouch-type rechargeable lithium batteries by using an ultrathick high-discharge capacity Li1.2Ni0.13Co0.13Mn0.54O2 cathode with an areal capacity exceeding 10 mAh/cm2 and a lithium metal anode. The high charge-discharge voltage of the lithium-rich manganese-based oxides allows for a higher lithium-ion storage capacity.
“The anode electrode employs ultrathin metal lithium incorporated using a separator coating technique, which addresses the annoying issue of reversible deposition of ultrathin lithium of large surface capacity,” explains first author Quan Li.
The devices boast a gravimetric energy density of 711.3 Wh/kg and a volumetric energy density of 1653.65 Wh/L, both of which are the highest in rechargeable lithium batteries based on an intercalation-type cathode, Li tells Physics World.
“With respect to the battery manufacture, our extremity battery structure design (including the use of ultrathin current collectors) was tailored to minimize the usage of auxiliary materials while enhancing the proportion of active materials in the entire battery,” he adds. “This synergistic approach is what enabled the ultrahigh energy density of the batteries.”
A 700 Wh/kg rechargeable pouch type lithium battery
Chinese Physics Letters 40(4) March 2023
DOI: 10.1088/0256-307X/40/4/048201
Quan LiYang YangXiqian YuXiqian YuHong Li
Abstract
High-energy-density rechargeable lithium batteries are being pursued by researchers because of their revolutionary potential nature. Current advanced practical lithium-ion batteries have an energy density of around 300 Wh kg ⁻¹ . Continuing to increase the energy density of batteries to a higher level could lead to a major explosion development in some fields, such as electric aviation.
Here, we have manufactured practical pouch-type rechargeable lithium batteries with both a gravimetric energy density of 711.3 Wh kg ⁻¹ and a volumetric energy density of 1653.65 Wh L ⁻¹ . This is achieved through the use of high-performance battery materials including high-capacity lithium-rich manganese-based cathode and thin lithium metal anode with high specific energy, combined with extremely advanced process technologies such as high-loading electrode preparation and lean electrolyte injection, etc. In this battery material system, the structural stability of cathode material at a widened charge/discharge voltage range and the deposition/dissolution behavior of interfacial modified thin lithium electrode are studied.
