Needle-punched electret air filters (NEAFs) with high filtration efficiency, low filtration resistance, and superior dust holding capacity

Air purification can effectively capture particulate matter and reduce the health risk from indoor air pollution. However, it remains a challenge to fabricate filtration materials with high filtration efficiency, low filtration resistance, and large dust holding capacity at the same time. Herein, we report Needle-punched Electret Air Filters (NEAFs) not only exhibiting the abovementioned performance, but also owning superior charge and filtration stability. By employing corona charging and MgSt charge enhancing additives, NEAFs exhibited high filtration efficiency (99.2%) and ultralow filtration resistance (13.93 Pa). Importantly, NEAFs only had 0.6% decline in filtration efficiency after heat treatment, which was much better than commercial meltblown materials. In addition, the needle-punching technique generated a unique 3D fluffy structure, resulting in a large dust holding capacity of 23.6 g m−2. Our design of NEAFs may provide new guidelines for next-generation high-performance air filtration materials.