Teracube is not backed by VC but the founders themselves. They provide free battery replacements (not just one time but as many as it takes throughout the 4-year warranty). It is true that users cannot replace the battery themselves but that's why the warranty comes with free parts, labor and two-way shipping.
The business idea is that by prolonging the phone's life, we can reduce 1/ e-waste (45M tons of e-waste produced by US and 135M WW) produced by people discarding their old phones, and 2/ raw materials used to produce the phones which not only the planet is running short but also the pollution caused during mining and manufacturing process.
