The increasing use of lithium-ion batteries in various applications has led to growing concerns about their disposal at the end of their service life and the associated environmental impacts. Meeting this challenge requires a paradigm shift towards sustainable practices that go beyond the conventional recycling approach. Within the framework of IEA Task 51, BFH and SIPBB will develop evaluation criteria for system selection, strategies for battery disassembly/reuse/reuse, and optimized operating conditions for so-called second-life applications.